Systems, devices, and methods for wireless communications in analyte monitoring systems

ABSTRACT

Systems, devices and methods are provided that allow for enhanced performance, power efficiency, interoperability, data security and user privacy for in vivo analyte monitoring systems that utilize wireless communications. The in vivo analyte monitoring systems can include a Bluetooth or Bluetooth Low Energy enabled handheld relay device for wirelessly relaying analyte data between a sensor unit device and one or more reader devices. The in vivo analyte monitoring systems can employ advertisement and encryption schemes for wirelessly transmitting data in a manner that allows for improved security, efficiency and privacy.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/541,572, filed Aug. 15, 2019, which is a continuation ofU.S. patent application Ser. No. 15/846,172, filed Dec. 18, 2017, nowabandoned, which claims priority to and the benefit of U.S. ProvisionalPatent Application No. 62/437,014, filed Dec. 20, 2016, all of which areincorporated by reference herein in its entirety for all purposes.

FIELD

The subject matter described herein relates to systems, devices, andmethods for wireless communications in analyte monitoring devices.

BACKGROUND

The detection and/or monitoring of analyte levels, such as glucose,ketones, lactate, oxygen, hemoglobin A1C, or the like, can be vitallyimportant to the health of an individual having diabetes. Patientssuffering from diabetes mellitus can experience complications includingloss of consciousness, cardiovascular disease, retinopathy, neuropathy,and nephropathy. Diabetics are generally required to monitor theirglucose levels to ensure that they are being maintained within aclinically safe range, and may also use this information to determine ifand/or when insulin is needed to reduce glucose levels in their bodiesor when additional glucose is needed to raise the level of glucose intheir bodies.

Growing clinical data demonstrates a strong correlation between thefrequency of glucose monitoring and glycemic control. Despite suchcorrelation, many individuals diagnosed with a diabetic condition do notmonitor their glucose levels as frequently as they should due to acombination of factors including convenience, testing discretion, painassociated with glucose testing, and cost.

As described in further detail below, one type of monitoring system isan in vivo analyte monitoring system, in which a sensor control devicemay be worn on the body of an individual that requires analytemonitoring. The sensor control device may have a small form-factor toincrease comfort and convenience for the individual. The sensor controldevice may also be configured to wirelessly transmit analyte data toanother device, on which the individual or her health care provider(HCP) can review the individual's data and make therapy decisions. Dueto certain aspects of wireless communication protocols and the compactsize of the sensor control device in these in vivo analyte monitoringsystems, problems may arise relating to power management, signal noiseinterference, interoperability, data security and privacy.

For these and other reasons, needs exist for improved analyte monitoringsystems, devices, and methods.

SUMMARY

The use of wireless communication protocols within an in vivo analytemonitoring system may present problems relating to power management,signal noise interference, interoperability, data security and privacy,to name a few. These problems can arise because manufacturers of sensorcontrol devices may have little control over a user's reader devices(e.g., smartphones) and their associated operating systems. For example,a reader device's operating system may require that a sensor controldevice turn its communication circuitry (e.g., its transceiver) on andoff at a frequent rate, which can create signal noise interference andrapid power consumption in the sensor control device. In addition, thirdparty user interface applications on the reader device may preventimportant information from being conveyed to and/or received by theuser.

Furthermore, in recent years, the threat of unauthorized tracking ofwireless devices has become a greater concern. For example, thirdparties may surreptitiously operate wireless device “trackers” atvarious geographical locations, which are designed to track the movementof an individual through a particular region based on an address of thewireless device. Thus, manufacturers have a need for enhanced privacycountermeasures, in particular, because in many embodiments, sensorcontrol devices are designed to be continuously worn on the body of theuser.

A number of embodiments of systems, devices and methods are providedthat allow for improved power management, operation, interoperability,security and privacy for in vivo analyte monitoring systems utilizingwireless communication protocols. For example, in certain embodiments, ahandheld relay device can be used to relay data indicative of a sensedanalyte level between a sensor control device and one or more readerdevices. In some embodiments, power latch circuitry can be used toactivate devices having a test strip interface. As described herein,these embodiments and others can allow for reduced power consumption bysensor control devices and improved interoperability with a diverserange and number of reader devices and their respective operatingsystems. In further embodiments, advertising schemes for wirelessprotocols are described which can allow for increased security throughencrypted analyte data carried in advertisement communications andenhanced privacy through anti-tracking routines.

Other systems, devices, methods, features and advantages of the subjectmatter described herein will become apparent to one with skill in theart upon examination of the following figures and detailed description.It is intended that all such additional systems, devices, methods,features and advantages be included within this description, be withinthe scope of the subject matter described herein, and be protected bythe accompanying claims. In no way should the features of the exampleembodiments be construed as limiting the appended claims, absent expressrecitation of those features in the claims.

BRIEF DESCRIPTION OF THE FIGURES

The details of the subject matter set forth herein, both as to itsstructure and operation, may be apparent by study of the accompanyingfigures, in which like reference numerals refer to like parts. Thecomponents in the figures are not necessarily to scale, emphasis insteadbeing placed upon illustrating the principles of the subject matter.Moreover, all illustrations are intended to convey concepts, whererelative sizes, shapes and other detailed attributes may be illustratedschematically rather than literally or precisely.

FIG. 1A is a high level diagram depicting an example embodiment of an invivo analyte monitoring system.

FIG. 1B is a high level diagram depicting another example embodiment ofan in vivo analyte monitoring system in which a handheld relay device isused.

FIG. 2A is a block diagram depicting an example embodiment of a readerdevice.

FIG. 2B is a block diagram depicting an example embodiment of a handheldrelay device.

FIGS. 2C-D are block diagrams depicting example embodiments of a sensorcontrol device.

FIG. 3 is a flow diagram depicting example embodiments of methods formonitoring and alarming in a handheld relay device.

FIGS. 4A-B are topology diagrams depicting examples of wireless networktopologies for use with an in vivo analyte monitoring system.

FIG. 5A is a timeline diagram depicting an example embodiment of anadvertising scheme for use with an in vivo analyte monitoring system.

FIG. 5B is a timeline diagram depicting another example embodiment of anadvertising scheme for use with an in vivo analyte monitoring system.

FIG. 5C is a flow diagram depicting an example embodiment of a methodfor resolving a resolvable address in an advertisement packet.

FIGS. 6A-B are block diagrams depicting example embodiments ofadvertisement packets comprising analyte data.

FIG. 7A is a block diagram depicting an example embodiment of a handheldreader device with power latch circuitry.

FIG. 7B is a schematic diagram depicting an example embodiment of powerlatch circuitry.

DETAILED DESCRIPTION

Before the present subject matter is described in detail, it is to beunderstood that this disclosure is not limited to the particularembodiments described, as such may, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of the present disclosure will be limited onlyby the appended claims.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present disclosure isnot entitled to antedate such publication by virtue of prior disclosure.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

It should be noted that all features, elements, components, functions,and steps described with respect to any embodiment provided herein areintended to be freely combinable and substitutable with those from anyother embodiment. If a certain feature, element, component, function, orstep is described with respect to only one embodiment, then it should beunderstood that that feature, element, component, function, or step canbe used with every other embodiment described herein unless explicitlystated otherwise. This paragraph therefore serves as antecedent basisand written support for the introduction of claims, at any time, thatcombine features, elements, components, functions, and steps fromdifferent embodiments, or that substitute features, elements,components, functions, and steps from one embodiment with those ofanother, even if the following description does not explicitly state, ina particular instance, that such combinations or substitutions arepossible. It is explicitly acknowledged that express recitation of everypossible combination and substitution is overly burdensome, especiallygiven that the permissibility of each and every such combination andsubstitution will be readily recognized by those of ordinary skill inthe art.

Generally, embodiments of the present disclosure are used with systems,devices, and methods for detecting at least one analyte, such asglucose, in a bodily fluid (e.g., subcutaneously within the interstitialfluid (“ISF”) or blood, within the dermal fluid of the dermal layer, orotherwise). Accordingly, many embodiments include in vivo analytesensors structurally configured so that at least a portion of the sensoris, or can be, positioned in the body of a user to obtain informationabout at least one analyte of the body. It should be noted, however,that the embodiments disclosed herein can be used with in vivo analytemonitoring systems that incorporate in vitro capability, as well aspurely in vitro or ex vivo analyte monitoring systems, including thosesystems that are entirely non-invasive.

Furthermore, for each and every embodiment of a method disclosed herein,systems and devices capable of performing each of those embodiments arecovered within the scope of the present disclosure. For example,embodiments of sensor control devices are disclosed and these devicescan have one or more sensors, analyte monitoring circuits (e.g., ananalog circuit), memories (e.g., for storing instructions), powersources, communication circuits, transmitters, receivers, processorsand/or controllers (e.g., for executing instructions) that can performany and all method steps or facilitate the execution of any and allmethod steps. These sensor control device embodiments can be used andcan be capable of use to implement those steps performed by a sensorcontrol device from any and all of the methods described herein.

Likewise, embodiments of handheld relay devices and reader devices aredisclosed having one or more transmitters, receivers, memories (e.g.,for storing instructions), power sources, processors and/or controllers(e.g., for executing instructions) that can perform any and all methodsteps or facilitate the execution of any and all method steps. Theseembodiments of the handheld relay devices and reader devices can be usedto implement those steps performed by a handheld relay device or readerdevice from any and all of the methods described herein.

Embodiments of trusted computer systems are also disclosed. Thesetrusted computer systems can include one or more processors,controllers, transmitters, receivers, memories, databases, servers,and/or networks, and can be discretely located or distributed acrossmultiple geographic locales. These embodiments of the trusted computersystems can be used to implement those steps performed by a trustedcomputer system from any and all of the methods described herein.

As mentioned, a number of embodiments of systems, devices, and methodsare described herein that provide for improved power management,interoperability, data security and privacy for in vivo analytemonitoring systems which utilize wireless communications. Theseembodiments further allow for signal noise reduction and reduced powerconsumption by the sensor control device; centralized management ofwireless connections between multiple and disparate reader devicesthrough the use of a handheld relay device; enhanced security andprivacy measures for wireless communications; to name a few features.Before describing these aspects of the embodiments in detail, however,it is first desirable to describe examples of devices that can bepresent within, for example, an in vivo analyte monitoring system, aswell as examples of their operation, all of which can be used with theembodiments described herein.

There are various types of in vivo analyte monitoring systems.“Continuous Analyte Monitoring” systems (or “Continuous GlucoseMonitoring” systems), for example, can transmit data from a sensorcontrol device to a reader device continuously without prompting, e.g.,automatically according to a schedule. “Flash Analyte Monitoring”systems (or “Flash Glucose Monitoring” systems or simply “Flash”systems), as another example, can transfer data from a sensor controldevice in response to a scan or request for data by a reader device,such as with a Near Field Communication (NFC) or Radio FrequencyIdentification (RFID) protocol. In vivo analyte monitoring systems canalso operate without the need for finger stick calibration.

In vivo analyte monitoring systems can be differentiated from “in vitro”systems that contact a biological sample outside of the body (or rather“ex vivo”) and that typically include a meter device that has a port forreceiving an analyte test strip carrying a bodily fluid of the user,which can be analyzed to determine the user's blood sugar level.

In vivo monitoring systems can include a sensor that, while positionedin vivo, makes contact with the bodily fluid of the user and senses theanalyte levels contained therein. The sensor can be part of a sensorcontrol device that resides on the body of the user and contains theelectronics and power supply that enable and control the analytesensing. The sensor control device, and variations thereof, can also bereferred to as a “sensor control unit,” an “on-body electronics” deviceor unit, an “on-body” device or unit, or a “sensor data communication”device or unit, to name a few.

In vivo monitoring systems can also include one or more reader devicesthat receive sensed analyte data from the sensor control device eitherdirectly or through a handheld relay device, as described in furtherdetail below. These reader devices can process and/or display the sensedanalyte data, in any number of forms, to the user. These devices, andvariations thereof, can be referred to as “handheld reader devices,”“reader devices” (or simply, “readers”), “handheld electronics” (orhandhelds), “portable data processing” devices or units, “datareceivers,” “receiver” devices or units (or simply receivers), or“remote” devices or units, to name a few. Other devices such as personalcomputers have also been utilized with or incorporated into in vivo andin vitro monitoring systems.

As further described herein, in vivo monitoring systems can also includea handheld relay device that relays sensed analyte data from the sensorcontrol device to a reader device. In a general sense, the handheldrelay device can include many of the same functionalities as the readerdevice. However, the handheld relay device may also include fewerfeatures, such as a non-graphical user interface. In addition, becausethe handheld relay device and the sensor control device are oftenprovided by the same manufacturer, the handheld relay device may alsoinclude additional features not present on reader devices. For example,the handheld relay device may be configured to communicate directly witha sensor control device using a proprietary wireless protocol, andfurther, can be configured to serve as a central hub from which sensedanalyte data can be transmitted to one or more reader devices.Similarly, the handheld relay device can be configured to monitor itselffor failure conditions according to parameters that are more rigorous orstringent than reader devices.

For reasons described with more detail below, the use of standardwireless communication protocols within an in vivo analyte monitoringsystem can pose challenges relating to power management, signal noiseinterference, interoperability, data security and privacy, to name afew. For wireless communications between a sensor control device and areader device (e.g., a smartphone), for example, the reader device'soperating system may require that the sensor control device turn itscommunication circuitry (e.g., its transceiver) on and off at arelatively frequent rate. This can create undesirable effects within thein vivo analyte monitoring system such as signal noise interference withsensitive analog sensor readings and rapid power consumption in thesensor control device.

As another example, the periodic release of new and updated operatingsystem software on reader devices may present interoperabilitychallenges in that a sensor control device may not be easily upgraded.Likewise, manufacturers of sensor control devices may have littlecontrol over reader devices, particularly where the reader device is asmartphone. In this regard, use of a reader device as a primary displaydevice within an in vivo analyte monitoring system can be problematic inthat manufacturers cannot control third party user interfaceapplications installed on the reader device, which may obscure or impairimportant data, alerts and/or alarms. Thus, a need exists to ensure thatsensor control devices and/or reader devices can be operated in a mannerthat is power efficient, does not interfere with sensor readings, anddoes not prevent important information from reaching the user.

Furthermore, in recent years, threats relating to the security andprivacy of sensitive data communicated within a wireless in vivo analytemonitoring system, such as, for example, “man-in-the-middle” attacksand/or unauthorized tracking of wireless devices, have become a greaterconcern. As one example, third parties may intercept sensitive patienthealth information contained within wireless communications between asensor control device and a reader device during a data transmissionprocedure. As another example, third parties may surreptitiously operatewireless device “trackers” at various geographical locations, which aredesigned to track the movement of an individual through a particularregion based on an address of the wireless device. While certainwireless communication protocols have included countermeasures againstsuch “trackers,” e.g., through the use of random and/or resolvableaddresses in Bluetooth and Bluetooth Low Energy devices, thesecountermeasures have been shown to be inadequate. For instance,third-party trackers can be programmed to associate two or more randomlygenerated addresses with a particular wireless device. Based on asequence of observable events in which a first device addressdisappears, followed by the appearance of a second device address, atracker may deduce that the two device addresses correlate with a singlewireless device.

The aforementioned problems, as well as others described below, areparticularly amplified with regards to wireless communications in vivoanalyte monitoring systems, since sensor control devices usually have alimited power supply and are designed to be continuously worn on thebody of the user. The claimed solutions disclosed herein do not simplytransplant a pre-existing practice or problem-solving method into acomputer-based environment. Rather, these embodiments specificallyaddress issues of power efficiency, interoperability, privacy andsecurity that exist solely due to the environment of wirelesscommunications within in vivo analyte monitoring systems. By way of anon-limiting example, some embodiments described herein utilize ahandheld relay device between the sensor control unit and a readerdevice (e.g., smart phone). In these embodiments, the handheld relaydevice can be configured to communicate with the sensor control deviceusing a proprietary wireless protocol, relay data with one or morereader devices, and/or install software updates relating to the variousmobile operating systems of the one or more reader devices. In theseexample embodiments, the sensor control device can operate with reducedsignal noise interference, greater power efficiency and fewerinteroperability issues. In other example embodiments, to reduce thechance of “main-in-the-middle” attacks, the sensor control device can beconfigured to enter a state in which it exclusively accepts data andconnection requests from the handheld relay device, and moreover,controls the timing interval of communications therewith. In still otherexample embodiments, to enhance privacy and data transmissionefficiency, the sensor control device can utilize advertising schemeswherein multiple and overlapping device addresses are utilized and/orencrypted data can be placed within advertising packets. These exampleembodiments, as well as others described below, are necessarily rootedin the computer-based technology of wireless communications within invivo analyte monitoring systems.

Furthermore, for all of the same reasons stated above, these solutionsare directed to specific improvements in wireless communications withinin vivo analyte monitoring systems, which indisputably constitute acomputer-related technology. As one specific example, the use of aproprietary wireless protocol between the sensor control device and ahandheld relay device enables the sensor control device to turn on andoff the radio transmitter less frequently, resulting in greater powerefficiency, less noise, and ultimately, improved sensor performance.Similarly, the use of a handheld relay device to interoperate withmultiple reader devices allows for less consumption of power andresources on the sensor control device, and ultimately improvedperformance. Likewise, the use of a wireless communication advertisingscheme with multiple and overlapping device addresses reflects aspecific improvement in the privacy and security of data wirelesslytransmitted by the sensor control device. Indeed, the elements of eachembodiment described herein, when viewed both individually and as anordered combination, amount to a significant and specific advancement inthe technology of wireless communications, and in particular, the powerefficiency, interoperability, security and privacy of patient datawithin in vivo analyte monitoring systems. For these reasons, as well asothers, these embodiments are not abstract.

Example Embodiments of In Vivo Analyte Monitoring Systems

FIG. 1A is an illustrative view depicting an example of an in vivoanalyte monitoring system 100A having a sensor control device 102 and areader device 120 that communicate with each other over a localcommunication path (or link) 140, which can be wired or wireless, anduni-directional or bi-directional. In embodiments where path 140 iswireless, a near field communication (NFC) protocol, RFID protocol,Bluetooth or Bluetooth Low Energy protocol, Wi-Fi protocol, proprietaryprotocol, or the like can be used, including those communicationprotocols in existence as of the date of this filing or their laterdeveloped variants.

Bluetooth is a well-known standardized short range wirelesscommunication protocol, and Bluetooth Low Energy is a version of thesame that requires less power to operate. Bluetooth Low Energy(Bluetooth LE, BTLE, BLE) is also referred to as Bluetooth Smart orBluetooth Smart Ready. BTLE is described in the Bluetooth Specification,version 4.0, published Jun. 30, 2010, and version 4.2, published Dec. 2,2014, both of which are explicitly incorporated by reference herein forall purposes. The term “NFC” applies to a number of protocols (orstandards) that set forth operating parameters, modulation schemes,coding, transfer speeds, frame format, and command definitions for NFCdevices. The following is a non-exhaustive list of examples of theseprotocols, each of which (along with all of its sub-parts) isincorporated by reference herein in its entirety for all purposes:ECMA-340, ECMA-352, ISO/IEC 14443, ISO/IEC 15693, ISO/IEC 18000-3,ISO/IEC 18092, and ISO/IEC 21481.

Reader device 120 is also capable of wired, wireless, or combinedcommunication with a remote computer system 170 over communication path(or link) 141 and with trusted computer system 180 through network 190and over communication path (or link) 142. Communication paths 141 and142 can be part of a telecommunications network, such as a Wi-Finetwork, a local area network (LAN), a wide area network (WAN), theinternet, or other data network for uni-directional or bi-directionalcommunication. Trusted computer system 180 can be accessed throughnetwork 190. In an alternative embodiment, communication paths 141 and142 can be the same path. All communications over paths 140, 141, and142 can be encrypted and sensor control device 102, reader device 120,remote computer system 170, and trusted computer system 180 can each beconfigured to encrypt and decrypt those communications sent andreceived.

Variants of devices 102 and 120, as well as other components of an invivo-based analyte monitoring system that are suitable for use with thesystem, device, and method embodiments set forth herein, are describedin US Patent Application Publ. No. 2011/0213225 (the '225 Publication),which is incorporated by reference herein in its entirety for allpurposes.

Sensor control device 102 can include a housing 103 containing in vivoanalyte monitoring circuitry and a power source. The in vivo analytemonitoring circuitry is electrically coupled with an analyte sensor 104that extends through an adhesive patch 105 and projects away fromhousing 103. Adhesive patch 105 contains an adhesive layer (not shown)for attachment to a skin surface of the body of the user. Other forms ofbody attachment to the body may be used, in addition to or instead ofadhesive.

Sensor 104 is adapted to be at least partially inserted into the body ofthe user, where it can make fluid contact with that user's bodily fluid(e.g., ISF, dermal fluid, or blood) and be used, along with the in vivoanalyte monitoring circuitry, to measure analyte-related data of theuser. Sensor 104 and any accompanying sensor control electronics can beapplied to the body in any desired manner. For example, also shown inFIG. 1A is an embodiment of insertion device 150 that, when operated,transcutaneously (or subcutaneously) positions a portion of analytesensor 104 through the user's skin and into contact with the bodilyfluid, and positions sensor control device 102 with adhesive patch 105onto the skin. In other embodiments, insertion device 150 can positionsensor 104 first, and then accompanying sensor control electronics canbe coupled with sensor 104 afterwards, either manually or with the aidof a mechanical device. Other devices, systems, and methods that may beused with embodiments herein, including variations of sensor controldevice 102, are described, e.g., in U.S. Patent Publication Nos.2010/0324392, 2011/0106126, 2011/0190603, 2011/0191044, 2011/0082484,2011/0319729, and 2012/0197222, the disclosures of each of which areincorporated herein by reference for all purposes.

After collecting the analyte-related data, sensor control device 102 canthen wirelessly communicate that data (such as, for example, datacorresponding to monitored analyte level and/or monitored temperaturedata, and/or stored historical analyte related data) to a reader device120 where, in certain embodiments, it can be algorithmically processedinto data representative of the analyte level of the user and thendisplayed to the user and/or otherwise incorporated into a diabetesmonitoring regime.

As shown in FIG. 1A, reader device 120 includes a display 122 to outputinformation to the user and/or to accept an input from the user (e.g.,if configured as a touch screen), and one optional input component 121(or more), such as a button, actuator, touch sensitive switch,capacitive switch, pressure sensitive switch, jog wheel or the like, toinput data, commands, or otherwise control the operation of readerdevice 120.

In certain embodiments, input component 121 of reader device 120 mayinclude a microphone and reader device 120 may include softwareconfigured to analyze audio input received from the microphone, suchthat functions and operation of the reader device 120 may be controlledby voice commands. Voice commands can include commands to input data,power cycle a device, retrieve data from sensor control device 102,display data and/or reports, and perform other like operations. Incertain embodiments, an output component of reader device 120 includes aspeaker (not shown) for outputting information as audible signals.Similar voice responsive components such as a speaker, microphone andsoftware routines to generate, process and store voice driven signalsmay be provided to sensor control device 102.

In certain embodiments, display 122 and input component 121 may beintegrated into a single component, for example, where the display candetect the presence and location of a physical contact touch upon thedisplay, such as a touch screen user interface. In such embodiments, theuser may control the operation of reader device 120 by utilizing a setof pre-programmed motion commands, including, but not limited to, singleor double tapping the display, dragging a finger or instrument acrossthe display, motioning multiple fingers or instruments toward oneanother, motioning multiple fingers or instruments away from oneanother, or other gestures. In certain embodiments, a display includes atouch screen having areas of pixels with single or dual functioncapacitive elements that serve as LCD elements and touch sensors.

Reader device 120 also includes one or more data communication ports 123for wired data communication with external devices such as a remoteterminal, e.g., a personal computer. Example data communication portsinclude USB ports, mini USB ports, USB Type-C ports, USB micro-A and/ormicro-B ports, RS-232 ports, Ethernet ports, Firewire ports, or othersimilar data communication ports configured to connect to the compatibledata cables. Reader device 120 may also include an integrated orattachable in vitro glucose meter, including an in vitro test strip port(not shown) to receive an in vitro glucose test strip for performing invitro blood glucose measurements.

Referring still to FIG. 1A, display 122 can be configured to display avariety of information—some or all of which may be displayed at the sameor at different times on display 122. The displayed information can beuser-selectable so that a user can customize the information shown on agiven display screen. Display 122 may include, but is not limited to,graphical display 138, for example, providing a graphical output ofcurrent analyte values in real time or over a monitored time period,which may show: markers such as meals, exercise, sleep, heart rate,blood pressure, etc.; numerical display 132, for example, providingmonitored glucose values (acquired or received in response to therequest for the information); and trend or directional arrow display 131that indicates a rate of analyte change and/or a rate of the rate ofanalyte change, e.g., by moving locations on display 122.

As further shown in FIG. 1A, display 122 may also include: date display135, which can provide date information for the user; time of dayinformation display 139 providing time of day information to the user;battery level indicator display 133 graphically showing the condition ofthe battery (rechargeable or disposable) of reader device 120; sensorcalibration status icon display 134, for example, in monitoring systemsthat require periodic, routine or a predetermined number of usercalibration events notifying the user that the analyte sensorcalibration is necessary; audio/vibratory settings icon display 136 fordisplaying the status of the audio/vibratory output or alarm state; andwireless connectivity status icon display 137 that provides indicationof wireless communication connection with other devices such as sensorcontrol device 102, remote computer system 170, and/or trusted computersystem 180. Display 122 may further include simulated touch screenbuttons 125, 126 for accessing menus, changing display graph outputconfigurations or otherwise controlling the operation of reader device120.

In certain embodiments, reader device 120 can be configured to outputalarms, alert notifications, glucose values, etc., which may be visual,audible, tactile, or any combination thereof. Reader device 120 mayinclude other output components such as a speaker, vibratory outputcomponent and the like to provide audible and/or vibratory outputindications to the user in addition to the visual output indicationprovided on display 122. For example, an output unit or display 122 ofreader device 120 may be configured to progressively increase ordecrease an associated auditory or vibratory signal over a predeterminedtime period. The output unit of display 122 of the reader device may befurther configured to output one or more of a visual, auditory orvibratory signal associated with a connection status associated withanother device (e.g., sensor control device 102 or handheld relay device200). Further details and other display embodiments can be found in,e.g., U.S. Patent Publication No. 2011/0193704, which is incorporatedherein by reference for all purposes.

Reader device 120 can be connected to a remote terminal 170, such as apersonal computer, which can be used by the user or a medicalprofessional to display and/or analyze the collected analyte data.Reader device 120 can also be connected to a trusted computer system 180that can be used for authentication of a third party softwareapplication. In both instances, reader device 120 can function as a dataconduit to transfer the stored analyte level information from the sensorcontrol device 102 to remote terminal 170 or trusted computer system180. In certain embodiments, the received data from the sensor controldevice 102 may be stored (permanently or temporarily) in one or morememories of reader device 120.

Remote terminal 170 may be a personal computer, a server terminal, alaptop computer, a tablet, or other suitable data processing device.Remote terminal 170 can be (or include) software for data management andanalysis and communication with the components in analyte monitoringsystem 100. Operation and use of remote terminal 170 is furtherdescribed in the'225 Publication incorporated herein. Analyte monitoringsystem 100 can also be configured to operate with a data processingmodule (not shown), also as described in the incorporated '225Publication.

Trusted computer system 180 can be within the possession of themanufacturer or distributor of sensor control device 102, eitherphysically or virtually through a secured connection, and can be used toperform authentication of sensor control device 102. Trusted computersystem 180 can also be used for the storage of encryption keys, e.g.,identity resolution keys, which are further described below.

Referring now in further detail to reader device 120, that device 120can be a mobile communication device such as a mobile telephoneincluding, but not limited to, a Wi-Fi or internet enabled smart phone,tablet, or personal digital assistant (PDA). Examples of smart phonescan include those mobile phones based on a Windows® operating system,Android™ operating system, iPhone® operating system, Palm® WebOS™,Blackberry® operating system, or Symbian® operating system, with datanetwork connectivity functionality for data communication over aninternet connection and/or a local area network (LAN).

Reader device 120 can also be configured as a mobile smart wearableelectronics assembly, such as an optical assembly that is worn over oradjacent to the user's eye (e.g., a smart glass or smart glasses, suchas Google glasses, which is a mobile communication device). This opticalassembly can have a transparent display that displays information aboutthe user's analyte level (as described herein) to the user while at thesame time allowing the user to see through the display such that theuser's overall vision is minimally obstructed. The optical assembly maybe capable of wireless communications similar to a smart phone. Otherexamples of wearable electronics include devices that are worn around orin the proximity of the user's wrist (e.g., a watch, etc.), neck (e.g.,a necklace, etc.), head (e.g., a headband, hat, etc.), chest, or thelike.

FIG. 1B is an illustrative view depicting another example of an in vivoanalyte monitoring system 100B having a sensor control device 102, ahandheld relay device 200, and one or more reader devices 120. At a highlevel, in vivo analyte monitoring system 100B is similar to that ofsystem 100A (FIG. 1A), except that a handheld relay device 200 can beused to relay data indicative of the sensed analyte level received fromsensor control device 102 to one or more reader devices 120. In certainembodiments, handheld relay device 200 can be configured to act as a hubto which sensor control device 102 can directly transmit data, and inturn, handheld relay device 200 can transmit the received data to one ormore reader devices 120, which can be configured as endpoints. In thisregard, a sensor control device 102 is not required to communicatedirectly with reader device 120 as previously shown in system 100A (FIG.1A). Furthermore, sensor control device 102 can be configured to enterinto a state in which it only accepts connection requests and datarequests directly from handheld relay device 200. As described infurther detail below, in situations where the sensor control device 102and handheld relay device 200 are manufactured by the same entity, aproprietary communication protocol can also be used at communicationpath 143. In addition, the handheld relay device 200 may include a teststrip interface 224 for receiving analyte test strips and performing invitro analyte measurements, which in turn may be visually displayed on adisplay 222 of the handheld relay device, or transmitted to one or morereader devices 120.

For signal noise reduction, improved power management, enhancedsecurity, interoperability, and other reasons, it may be advantageous toutilize a handheld relay device 200 to relay data wirelesscommunications between sensor control device 102 and one or more readerdevices 120 within the in vivo analyte monitoring system 100B of FIG.1B.

In one aspect, handheld relay device 200 and sensor control device 102can be configured to use advertising and connection schemes in awireless LAN, for example, that are not supported by the operatingsystems of reader devices 120. For example, according to the BluetoothLow Energy (BTLE) standard protocol, each BTLE device can be configuredaccording to a set of connection parameters, including a connectioninterval maximum parameter. The connection interval maximum parametercan determine how often a BTLE controller device (e.g., handheld relaydevice 200) will ask for data from a BTLE peripheral device (e.g.,sensor control device 102). According to the BTLE standard protocol, theconnection interval must be between 7.5 milliseconds and 4 seconds. (See“Specification of the Bluetooth System, Covered Core Package version4.2, Volume 6” at page 76-77 (“4.5.1 Connection Events”).) Furthermore,third party manufacturers of reader devices may set their ownrequirements with regard to BTLE connection parameters. For example, forBTLE peripherals (e.g., sensor control devices 102) communicating withApple iOS devices, the connection interval parameter must be equal to orless than 2 seconds.

In some embodiments, handheld relay device 200 can be configured toreceive data transmissions from sensor control device 102 at aconnection interval greater than the connection intervals allowed bymobile operating systems (e.g., iOS and Android) of reader devices 120,thereby reducing the number of times the radio transmitter of sensorcontrol device 102 must turn on and off in a given period. Thispotentially reduces power consumption in sensor control device 102 and,moreover, can minimize signal noise interference from the radiotransmitter, which can adversely impact sensitive analog sensorreadings. By contrast, a handheld relay device 200 can be better suitedfor supporting multiple reader devices 120, because it can have a largerpower supply than the sensor control device 102 for the operation of itswireless communication circuitry, as well as fewer concerns regardingsignal noise interference.

In further embodiments, the in vivo analyte monitoring system of 100Ballow for enhanced security and interoperability. For example, aproprietary wireless protocol may be used between the sensor controldevice 102 and the handheld relay device 200, increasing the likelihoodthat data indicative of a sensed analyte level is transmitted from thesensor control device 102 to a handheld relay device 200 in a secure andpredictable manner. This can be advantageous because the sensor controldevice 102 may have limited power, memory (e.g., for storinginstructions), and processing capability (e.g., for executinginstructions). Use of a proprietary communication protocol can alleviatethe need for the sensor control device 102 to accommodate for a varietyof connection requirements attendant with the various operating systems(e.g., iOS, Android, Windows) of different reader devices, which can betaxing on a sensor control device 102 that may have limited resources.

Moreover, a proprietary communication protocol can offer improvedsecurity by mitigating the risk of “man-in-the-middle” attacks againstthe sensor control device 102 and a handheld relay device 200. Forexample, encryption keys can be generated and exchanged between sensorcontrol device 102 and handheld relay device 200 during a typicalpairing procedure in which a communication channel is establishedbetween the two devices. One of any number of key generation algorithms,which are known in the art, can be used to generate a private key and acorresponding public key. Examples of key generation algorithms that canbe used include, but are not limited to RSA algorithms such as thosedescribed in the Public-Key Cryptography Standards (PKCS). Any desiredkey length can be used, but keys with longer lengths will typicallyprovide more security. For example, key lengths of 128 bits, 256 bits,512 bits, 1024 bits, 2048 bits, and 4096 bits, as well as others, can beused.

According to the proprietary communication protocol, however, uponcompletion of the key exchange, the communication channel can be closedand need not remain open. Subsequently, data indicative of a sensedanalyte level can be encrypted by the sensor control device 102 using aprivate encryption key, and, in turn, decrypted by the handheld relaydevice 200 using a public encryption key. Accordingly, sensor controldevice 102 enters into a state in which it exclusively accepts data andconnection requests from handheld relay device 200, and moreover,controls the timing interval of communications with handheld relaydevice 200.

This configuration can provide several advantages over prior modes ofwireless communications in in vivo analyte monitoring systems, whereinhandheld relay device 200 manages the timing intervals betweencommunications. In those instances, where handheld relay device 200manages the timing of communications, sensor control device 102 would berequired to maintain and store previous data packets, to respond torequests from handheld relay device 200, while concurrently compilingnew data packets from analyte measurement data from the analyte sensor.This can be disadvantageous in that sensor control device 102 wouldrequire more power, storage and processing resources. In addition,simultaneous transmission and analyte measurements can have undesirableeffects, such as signal noise interference with the analyte sensor. Bycontrast, according to some embodiments of the present disclosure, ininstances where sensor control device 102 manages the timing intervalsbetween communications, sensor control device 102 can time thetransmissions with handheld relay device 200 to coincide with periods inbetween analyte measurements. As such, sensor control device 102 can beoptimized to use less power, storage and processing resources, as wellas avoid signal noise interference.

Furthermore, in embodiments where sensor control device 102 manages thetiming intervals between communications, handheld relay device 200 candiscern the timing of the sensor control device 102 from information inthe data packets. For example, sensor control device 102 can beconfigured to transmit data packets once per minute within a ten-secondwindow. The precise time within the ten-second window at which thepacket is sent can be determined by the packet number and the serialnumber of sensor control device 102. On initial connection with sensorcontrol device 102, handheld relay device 200 can listen for a signalfrom sensor control device 102 for up to a minute. Upon receiving afirst packet, handheld relay device 200 can analyze the packet numberand serial number of sensor control device 102, and thus discern thedata transmission timing of the next packet based on a knowntime-hopping algorithm. In other embodiments, sensor control device 102can similarly provide life count and patch ID information according to aknown time-hopping algorithm, such that the handheld relay device 200can discern the timing of sensor control device 102 after receiving thefirst packet.

Data received by handheld relay device 200 can also be encrypted (in asimilar manner described above with respect to data transmitted by thesensor control device 102) and stored in a memory 280 prior totransmission to one or more reader devices 120. Subsequently, dataindicative of a sensed analyte level and the in vitro blood analytemeasurements (e.g., test strip measurements) can be decrypted by thereader device 120 using a public encryption key and displayed to theuser.

Another example of an advantage provided through the use of handheldrelay device 200 can be increased interoperability. In particular, thefrequent release of new or updated operating systems for reader devices120 may necessitate an update to devices which interoperate with thereader devices. It can be advantageous to deploy new software and/orfirmware to a handheld relay device 200, instead of the sensor controldevice 102, which may include an application-specific interfacecircuitry (ASIC) that cannot be easily reprogrammed.

Referring again to FIG. 1B, communications paths 143 and 144 between thedevices shall be described in further detail. Sensor control device 102and the handheld relay device 200 can communicate with each other over alocal communication path (or link) 143, and handheld relay device 200and one or more reader devices can communicate with each other over oneor more local communication paths (or link) 144. Handheld relay device200 can be configured to serve as a hub between the sensor controldevice 102 and one or more reader devices 120. In this regard, handheldrelay device 200 can serve as a central device to accept and manageconnections to endpoints (e.g., reader devices 120), as well as relaythe sensed analyte data received from sensor control device 102.Communication paths 143 and/or 144 can each be uni-directional orbi-directional. In embodiments where paths 143 and/or 144 are wireless,a near field communication (NFC) protocol, RFID protocol, Bluetooth orBluetooth Low Energy protocol, Wi-Fi protocol, proprietary protocol orthe like can be used, including those communication protocols inexistence as of the date of this filing or their later developedvariants. In an alternative embodiment, communications paths 144 can bethe same path, for example, via a broadcasting or multi-castingcommunication. Further, all communications over paths 143 and/or 144 canbe encrypted, and sensor control device 102, handheld relay device 200,reader devices 120, remote computer system 170, and trusted computersystem 180 can each be configured to encrypt and decrypt thosecommunications sent and received.

As described above, a proprietary communication protocol can also beused at communication path 143, particularly in instances where thesensor control device 102 and the handheld relay device 200 aremanufactured and/or supported by the same company. The proprietarycommunication protocol can be, for example, a variation of a standardwireless communication protocol, in which certain parameters can beconfigured with values which exceed a threshold minimum or maximum valuein the standard protocol. As one example, for Bluetooth Low Energydevices, a connection interval maximum parameter can be implementedusing a value that exceeds the 4 second maximum value that is set forthin the standard.

As shown in FIG. 1B, handheld relay device 200 can include a display 222to output information to the user. For example, as depicted here,display 222 is outputting a current glucose level of 216 mg/dl. Handheldrelay device 200 can also include an optional input component 221, suchas a button, actuator, touch sensitive switch, capacitive switch,pressure sensitive switch, jog wheel or the like, to input data orcommands to handheld relay device 200 or otherwise control the operationof handheld relay device 200. In certain embodiments, an outputcomponent of handheld relay device 200 includes a speaker (not shown)for outputting information as audible signals.

Handheld relay device 200 also includes one or more data communicationports 223 for wired data communication with external devices such as aremote terminal, e.g., a personal computer. Example data communicationports include USB ports, mini USB ports, USB Type-C ports, USB micro-Aand/or micro-B ports, RS-232 ports, Ethernet ports, Firewire ports, orother similar data communication ports configured to connect to thecompatible data cables. Handheld relay device 200 may also include anintegrated or attachable in vitro glucose meter, including an in vitrotest strip interface 224 to receive an in vitro glucose test strip forperforming in vitro blood glucose measurements.

Referring still to FIG. 1B, display 222 can be configured to display avariety of information—some or all of which may be displayed at the sameor different time on display 222. Display 222 may include, but is notlimited to, providing a visual output of glucose values in real time orover a monitored time period; trend or directional arrow display thatindicates a rate of analyte change and/or a rate of the rate of analytechange. Display 222 may also include a date display; a time of daydisplay; a battery level indicator display; an impaired screen display;an audio/vibratory settings icon display; and a wireless connectivitystatus icon display for providing an indication of wirelesscommunication connection with devices such as sensor control device 102and reader device 120. In certain embodiments, display 222 of handheldrelay device 200 has fewer functionalities relative to, for example, thedisplay 122 of reader device 120. For example, as previously described,display 122 and input component 121 of reader device 120 may include agraphical display, a touch screen user interface, and/or other displayand input features of smart phone devices. By contrast, display 222 ofhandheld relay device 200, having a relatively small form factor, can belimited to a numerical display (i.e., does not have a graphical userinterface), as shown in FIG. 1B, and/or one or more directional arrowsto indicate a trend and/or rate of analyte change.

In certain embodiments, handheld relay device 200 can be configured tooutput alarms, alert notifications, glucose values, etc., which may bevisual, audible, tactile, or any combination thereof. Handheld relaydevice 200 may include other output components such as a speaker,vibratory output component and the like to provide audible and/orvibratory output indications to the user in addition to the visualoutput indication provided on display 222. For example, output unit 260of handheld relay device 200 (FIG. 2B) can be adapted to progressivelyincrease or decrease an associated auditory or vibratory signal over apredetermined time period in response to a monitored condition or event.

Handheld relay device 200 can be connected to one or more reader devices120, which can be used by the user to display and/or analyze thecollected analyte data. In turn, one or more reader devices 120, whichcan also be used by the user to display and/or analyze the collecteddata, can also be connected to a trusted computer system 180 that can beused for authentication of a third party software application or, asanother example, for the storage of data indicative of a sensed analytelevel. In both instances, handheld relay device 200 can function as adata conduit to transfer the stored analyte level information from thesensor control device 102 to one or more reader devices 120. In certainembodiments, the received data from the sensor control device 102 may bestored (permanently or temporarily) in one or more memories of handheldrelay device 200.

Referring again to FIG. 1B, it is noted that, in addition to thefeatures, functionalities and attributes described above with respect tothe in vivo analyte monitoring system of 100B, the sensor control device102, reader device 120, remote terminal 170, and trusted computer system180, and each of the components included therewith, can each have any ofthe features, functionalities and attributes as described with respectto the in vivo analyte monitoring system of 100A (FIG. 1A). Furthermore,although two reader devices 120 are depicted, system 100B may comprisethree, four, five or more similar or dissimilar reader devices 120.Similarly, system 100B can also comprise one reader device 120.

The processing of data within systems 100A and 100B can be performed byone or more control logic units or processors of the handheld relaydevice 200, one or more reader devices 120, remote terminal 170, trustedcomputer system 180, and/or sensor control device 102. For example, rawdata measured by sensor 104 (after conversion to digital form) can bealgorithmically processed into a value that represents the analyte leveland that is readily suitable for display to the user, and this can occurin sensor control device 102, handheld relay device 200, reader device120, remote terminal 170, or trusted computer system 180. Thisalgorithmic processing can include the calibration of the raw data, theapplication of environmental compensation (e.g., temperature-basedadjustments), the application of a proprietary algorithm, and the like.The information derived from the raw data can be displayed in any of themanners described above on any display of handheld relay device 200,reader device 120, remote terminal 170, or trusted computer system 180.

The information may be utilized by the user to determine any necessarycorrective actions to ensure the analyte level remains within anacceptable and/or clinically safe range. Other visual indicators,including colors, flashing, fading, etc., as well as audio indicators,including a change in pitch, volume, or tone of an audio output, and/orvibratory or other tactile indicators may also be incorporated into theoutputting of trend data as means of notifying the user of the currentlevel, direction, and/or rate of change of the monitored analyte level.For example, based on a determined rate of glucose change, programmedclinically significant glucose threshold levels (e.g., hyperglycemicand/or hypoglycemic levels), and current analyte level derived by an invivo analyte sensor, an algorithm stored on a computer readable mediumof systems 100A and 100B can be used to determine the time it will taketo reach a clinically significant level and can be used to output anotification in advance of reaching the clinically significant level,e.g., 30 minutes before a clinically significant level is anticipated,and/or 20 minutes, and/or 10 minutes, and/or 5 minutes, and/or 3minutes, and/or 1 minute, and so on, with outputs increasing inintensity or the like.

Example Embodiments of Reader Devices

FIG. 2A is a block diagram of an example embodiment of a reader device120 configured as a smart phone. Here, reader device 120 includes aninput component 121, display 122, and processing hardware 326, which caninclude one or more processors, microprocessors, controllers, and/ormicrocontrollers, each of which can be a discrete chip or distributedamongst (and a portion of) a number of different chips. Here, processinghardware 326 includes a communications processor 322 having on-boardmemory 323 and an applications processor 324 having on-board memory 325.Reader device 120 further includes an RF transceiver 328 coupled with anRF antenna 329, a memory 330, multi-functional circuitry 332 with one ormore associated antennas 334, a power supply 336, and power managementcircuitry 338. FIG. 2A is an abbreviated representation of the typicalhardware and functionality that resides within a smart phone and thoseof ordinary skill in the art will readily recognize that other hardwareand functionality (e.g., codecs, drivers, glue logic), can also beincluded.

Communications processor 322 can interface with RF transceiver 328 andperform analog-to-digital conversions, encoding and decoding, digitalsignal processing and other functions that facilitate the conversion ofvoice, video, and data signals into a format (e.g., in-phase andquadrature) suitable for provision to RF transceiver 328, which can thentransmit the signals wirelessly. Communications processor 322 can alsointerface with RF transceiver 328 to perform the reverse functionsnecessary to receive a wireless transmission and convert it into digitaldata, voice, and video.

Applications processor 324 can be adapted to execute the operatingsystem and any software applications that reside on reader device 120,process video and graphics, and perform those other functions notrelated to the processing of communications transmitted and receivedover RF antenna 329. The smart phone operating system will operate inconjunction with a number of applications on reader device 120. Anynumber of applications (also known as “user interface applications”) canbe running on reader device 120 at any one time, and will typicallyinclude one or more applications that are related to a diabetesmonitoring regime, in addition to the other commonly used applicationsthat are unrelated to such a regime, e.g., email, calendar, weather,sports, games, etc. For example, the data indicative of a sensed analytelevel and in vitro blood analyte measurements received by the readerdevice can be securely communicated to user interface applicationsresiding in memory 325 of the reader device 120. Such communications canbe securely performed, for example, through the use of mobileapplication containerization or wrapping technologies.

Memory 330 can be shared by one or more the various functional unitspresent within reader device 120, or can be distributed amongst two ormore of them (e.g., as separate memories present within differentchips). Memory 330 can also be a separate chip of its own. Memory 330 isnon-transitory, and can be volatile (e.g., RAM, etc.) and/ornon-volatile memory (e.g., ROM, flash memory, F-RAM, etc.).

Multi-functional circuitry 332 can be implemented as one or more chipsand/or components (e.g., transmitter, receiver, transceiver, and/orother communication circuitry) that perform other functions such aslocal wireless communications (e.g., for Wi-Fi, Bluetooth, Bluetooth LowEnergy, Near Field Communication (NFC), Radio Frequency Identification(RFID), and others) and determining the geographic position of readerdevice 120 (e.g., global positioning system (GPS) hardware). One or moreother antennas 334 are associated with the functional circuitry 332 asneeded to operate with the various protocols and circuits.

Power supply 336 can include one or more batteries, which can berechargeable or single-use disposable batteries. Power managementcircuitry 338 can regulate battery charging and power supply monitoring,boost power, perform DC conversions, and the like.

As mentioned, the reader device 120 may also include one or more datacommunication ports, such as USB ports, mini USB ports, USB Type-Cports, USB micro-A and/or micro-B ports, RS-232 ports, or any otherwired communication ports for data communication with a handheld relaydevice 200, remote terminal 170, trusted computer system 180, or sensorcontrol device 102, to name a few.

In further embodiments, reader devices 120 can be configured to receivedata wirelessly over communication links 140, 144 from sensor controldevice 102 or handheld relay device 200. For example, the wirelesscommunication circuitry 328, 334 of reader device 120 can be adapted toreceive data indicative of a sensed analyte level, including a currentanalyte level, such as real-time analyte level information, historicalanalyte levels, a rate of change of an analyte level over apredetermined time period, and a rate of the rate of change of ananalyte level. One or more processors 322, 324 can be configured toconvert the received data indicative of a sensed level into a userreadable form. The converted data can be communicated to the display 122for outputting information to the user in the form of one or morevisual, auditory or vibratory signals.

In still a further embodiment, the user using in vivo analyte monitoringsystem 100A or 100B (FIG. 1A or 1B) may manually input the blood glucosevalues using, for example, a user interface (for example, a keyboard,keypad, and the like) incorporated in reader device 120. In thealternative, a user may manually input blood glucose values using, forexample, a user interface incorporated in the handheld relay device 120or a remote terminal 170.

Example Embodiments of Handheld Relay Devices

FIG. 2B is a block schematic diagram depicting a handheld relay device200, as shown in FIG. 1B, in accordance with one embodiment of thepresent disclosure. Referring to FIG. 2B, the handheld relay device 200includes an analyte test strip interface 224, an RF transceiver 252, auser input 221, a temperature detection section 254, and a clock 255,each of which is operatively coupled to one or more processors 257. Ascan be further seen from the Figure, the handheld relay device 200 alsoincludes a power supply 256 operatively coupled to a power conversionand monitoring section 258. Further, the power conversion and monitoringsection 258 is also coupled to the one or more processors 257 of thehandheld relay device 200. Moreover, also shown are a serialcommunication section 259, and an output unit 260, each operativelycoupled to the one or more processors 257.

In one embodiment, the test strip interface 224 includes a test stripport adapted to receive a manual insertion of in vitro test strips andperform in vitro blood analyte measurements. The test strip can be usedto perform an in vitro measurement of a user's glucose level. Those ofordinary skill in the art will appreciate that in vitro measurements ofother analytes (e.g., ketones, lactate, hemoglobin A1C or the like) arewithin the scope of the present disclosure. In such a configuration,handheld relay device 200 can process a fluid sample on a test strip,determine an analyte level contained therein, and display that result toa user. Various types of in vitro test strips can be suitable for usewith handheld relay device 200. As a non-limiting example, test stripsmay be employed that only require a very small amount (e.g., onemicroliter or less, e.g., about 0.5 microliter or less, e.g., about 0.1microliter or less) of applied sample to the strip in order to obtainaccurate glucose information, e.g. FreeStyle® or Precision® bloodglucose test strips and systems from Abbott Diabetes Care Inc. Handheldrelay devices 200 with in vitro monitors and test strip ports may beconfigured to conduct in vitro analyte monitoring with no usercalibration in vitro test strips (i.e., no human interventioncalibration), such as FreeStyle Lite glucose test strips from AbbottDiabetes Care Inc. Detailed description of such test strips and devicesfor conducting in vitro analyte monitoring is provided in U.S. Pat. Nos.6,377,894, 6,616,819, 7,749,740, 7,418,285; U.S. Patent Publication Nos.2004/0118704, 2006/0091006, 2008/0066305, 2008/0267823, 2010/0094110,2010/0094111, and 2010/0094112, and 2011/0184264, the disclosure of eachof which are incorporated herein by reference for all purposes.

The in vitro analyte measurements can be communicated to the output unit260 for visually displaying on the display 222 of handheld relay device200, stored in non-volatile memory 280, or transmitted by the RFtransceiver 252 or multi-functional circuitry 253 to another device,e.g., one or more reader devices 120. This manual testing of glucose canbe used, for example, to calibrate sensor control unit 102 (shown inFIG. 1B).

In one embodiment, the RF transceiver 252 can be configured tocommunicate, via the communication links 143 and 144 (shown in FIG. 1B)with the communication circuitry 168 (shown in FIGS. 2C and 2D) of thesensor control device 102 or the RF transceivers of the one or morereader devices 120, to transmit and/or receive encoded data signals fromthe communication circuitry 168 (shown in FIGS. 2C and 2D) for, amongothers, signal mixing, demodulation, and other data processing. One ormore antennas 251 are associated with RF transceiver 252 as needed tooperate with the various protocols and circuits.

Multi-functional circuitry 253 can be implemented as one or more chipsand/or components (e.g., transmitter, receiver, transceiver, and/orother communication circuitry) that perform other functions such aslocal wireless communications (e.g., for Wi-Fi, Bluetooth, Bluetooth LowEnergy, Near Field Communication (NFC), Radio Frequency Identification(RFID), and others) and determining the geographic position of handheldrelay device 200 (e.g., global positioning system (GPS) hardware). Incertain embodiments, however, the wireless communication circuitry ofhandheld relay device 200 is limited in functionality, relative toreader device 120, for example, in that it does not include nativeGlobal System Mobile Communications (GSM) or Code Division MultipleAccess (CDMA) functionality. In one embodiment, the multi-functionalcircuitry 253 can be configured to communicate, via the communicationlinks 143 and 144 (FIG. 1B) with the communication circuitry 168 (shownin FIGS. 2C and 2D) of the sensor control device 102 and the RFtransceivers of the one or more reader devices 120, to transmit and/orreceive encoded data signals from the communication circuitry 168 (shownin FIGS. 2C and 2D) for, among others, signal mixing, demodulation, andother data processing. One or more antennas 261 are associated with thefunctional circuitry 253 as needed to operate with the various protocolsand circuits.

In a further embodiment, the handheld relay device 200 can be configuredto receive data wirelessly over communication link 143 from sensorcontrol device 102. For example, wireless communication circuitry 252,253 of handheld relay device 200 can be adapted to receive dataindicative of a sensed analyte level, including a current analyte level,such as real-time analyte level information, historical analyte levels,a rate of change of an analyte level over a predetermined time period,and a rate of the rate of change of an analyte level. One or moreprocessors 257 can be configured to convert the received data indicativeof a sensed level into a user readable form. The one or more processors257 can also be configured to convert in vitro analyte measurementsperformed by the test strip interface 224 into a user readable format.The converted data and measurements can be communicated to the outputunit 260 for outputting information to the user in the form of one ormore visual, auditory or vibratory signals.

The input device 221 of the handheld relay device 200 is configured toallow the user to enter information into the handheld relay device 200as needed. The temperature detection section 254 is configured toprovide temperature information of the handheld relay device 200 to theone or more processors 257, while the clock 255 provides, among others,real time information to the one or more processors 257. Furthermore,the input device 221 of the handheld relay device 200 is limited infunctionality, relative to the reader device 120, and does not include amicrophone or other voice-input functionalities.

Each of the various components of the handheld relay device 200 shown inFIG. 2B is powered by the power supply 256 which can include a battery.The battery can be a disposable, one-time use battery or a rechargeablebattery (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metalhydride (NiMH), lithium-ion (Li-ion)) that may be recharged by aseparate power supply recharging unit (not shown). Furthermore, thepower conversion and monitoring section 258 is configured to monitor thepower usage by the various components in the handheld relay device 200for effective power management and to alert the user, for example, inthe event of power usage which renders the handheld relay device 200 insub-optimal operating conditions. An example of such sub-optimaloperating condition may include, for example, operating the vibrationoutput mode (as discussed below) for a period of time thus substantiallydraining the power supply 256 while the one or more processors 257(thus, the handheld relay device 200) is turned on. Moreover, the powerconversion and monitoring section 258 may additionally be configured toinclude a reverse polarity protection circuit such as a field effecttransistor (FET) configured as a battery activated switch.

The serial communication section 259 in the handheld relay device 200 isconfigured to provide a bi-directional communication path from thetesting and/or manufacturing equipment for, among others,initialization, testing, and configuration of the handheld relay device200. Serial communication section 259 can also be used to upload data toa computer, such as time-stamped blood glucose data. The communicationlink with an external device (not shown) can be made, for example, bycable, infrared (IR) or RF link.

The output unit 260 of the handheld relay device 200 is coupled todisplay 222 and can provide, for example, numerical information fordisplay to a user (e.g., a current glucose level). Additionally, outputunit 260 may also include an integrated speaker for outputting audiblesignals as well as to provide vibration output as commonly found inhandheld electronic devices, such as mobile telephones presentlyavailable. In a further embodiment, the handheld relay device 200 alsoincludes an electro-luminescent lamp configured to provide backlightingto the output unit 260 for visual display in dark ambient surroundings.

Referring back to FIG. 2B, the handheld relay device 200 in oneembodiment may also include a storage section such as a programmable,non-volatile memory device 280 as part of the one or more processors 257(as shown here), or provided separately in the handheld relay device200, operatively coupled to the one or more processor 257. The one ormore processors 257 can be further configured to perform Manchesterdecoding, as well as error detection and correction upon the encodeddata signals received from the sensor control unit 102 via thecommunication link 143.

Example Embodiments of Monitoring, Alarming and Reporting Routines

In some embodiments, monitoring, alarming and reporting routines can bestored in memory and executed by one or more processors of the handheldrelay device 200 or a reader device 120. For example, a monitoringroutine, stored in memory 280 of handheld relay device 200, can beexecuted by one or more processors 257 to monitor the state of thewireless connections between handheld relay device 200 and the sensorcontrol device 102. The monitoring routine can further include a commandto output a visual, audio or vibratory alarm in response to a loss ofwireless connectivity with the sensor control device 102. In someembodiments, for example, a monitoring routine can include thetransmission of an alarm command from a handheld relay device 200 to areader device 120.

Similarly, monitoring routines for failure conditions can be stored inmemory of the handheld relay device 200 or the one or more readerdevices 120. As described earlier, the sensor control device 102 andhandheld relay device 200 may be manufactured and/or sold by the samecompany. By contrast, reader devices 120 (e.g., smartphone) can bemanufactured by various third parties, and may also include any numberof third party user interface applications. Thus, because themanufacturer of the handheld relay device 200 may have more control overits own devices, in some embodiments, the failure condition monitoringroutines of the handheld relay device 200 can be configured with agreater degree of rigor than the failure condition monitoring routinesof the reader device 120. The heightened rigor for the failure conditionmonitoring routines on a handheld relay device 200 can comprise, forexample, an increased rate of monitoring, the use of backgroundapplication processing, and/or the use and prioritization ofmultithreaded applications. Handheld relay device 200 can be configuredby a manufacturer, for example, to provide a higher degree of priorityfor failure condition monitoring routines, in terms of memoryallocation, processor usage, display usage and/or network bandwidth. Bycomparison, the degree of rigor (i.e., local prioritization) for failurecondition monitoring routines on a reader device 120 (e.g., smartphone),whose primary function may not be as a medical device, may beconstrained by the mobile operating system and/or other third-party userinterface applications. A failure condition monitoring routine on areader device 120, for example, may be placed into backgroundprocessing, or in a low-priority processing state, due to the presenceof other third-party user interface applications. Similarly, the failurecondition monitoring routine may enter into a suspended state and/or beunable to execute at all until it is returned to the foreground. Inaddition, reader devices 120 may not be capable of prioritizingdisplayable events and/or allocating reserved network bandwidth forfailure condition monitoring routines.

In some embodiments, the failure condition monitoring routine canfurther include a command to execute one or more predetermined fail-safeprocedures in response to the detection of one or more failureconditions. Optionally, the failure conditions and fail-safe proceduresmay be configurable by a user of handheld relay device 200, and mayfurther require that the user input a passcode through the user inputdevice 221 to confirm any changes thereto.

FIG. 3 is a flowchart diagram showing one embodiment of multiplemonitoring and alarming routines 350, 450 for a handheld relay device200 and a reader device 120. Turning to the handheld relay device 200,multiple monitoring and alarming routines 350 are stored in memory 280and executed by one or more processors 257. At Step 352, handheld relaydevice 200 is initialized, for example, by powering on or power cyclingthe device. At Step 354, handheld relay device 200 periodically performsa check to confirm that it has received data, e.g., data indicative of asensed analyte level, from sensor control device 102.

At Step 356, handheld relay device 200 evaluates the received data andthe state of the handheld relay device 200 for the occurrence of one ormore predetermined alarm conditions. In some embodiments, for example,predetermined alarm conditions may include the detection of ahypoglycemic or hyperglycemic condition, as determined from the sensedanalyte data received from the sensor control device 102 or the in vitroanalyte measurements determined for a test sample received through atest strip port; the power reserve of the handheld relay device 200; andthe wireless connectivity between handheld relay device 200 and sensorcontrol device 102. For example, a battery indicator icon on the display222 of the handheld relay device 200 may indicate the approximate amountof power left in the device. If no predetermined alarm conditions aredetermined, handheld relay device 200 can output a signal to the displayindicating a normal status, or in the alternative, no output is sent tothe display at all. If one or more predetermined alarm conditions aredetermined, at Step 358, the handheld relay device 200 can output analarm to the reader device 120 over communication path 144. Further, atStep 360, the handheld relay device 200 can also output an alarm to thelocal display, for example, and can also generate an auditory orvibratory signal. As seen in FIG. 3 , the monitoring and alarmingroutine 350 can return to Step 356 to continue checking forpredetermined alarm conditions.

In some embodiments, the handheld relay device 200 can concurrentlyexecute, by its one or more processors 257, instructions stored inmemory 280 for the monitoring of failure conditions. Referring again tothe monitoring and alarming routines 350 in FIG. 3 , at Step 362, thehandheld relay device 200 can periodically perform checks for one ormore predetermined failure conditions at a first rigor. In someembodiments, for example, the predetermined failure conditions caninclude monitoring for an impaired display condition, a low powercondition, a low data storage condition and a network communicationfailure condition. At Step 364, handheld relay device 200 determines ifone or more predetermined failure conditions has occurred. If so,handheld relay device 200 can perform one or more fail-safe proceduresat Step 366. In some embodiments, the fail-safe procedures can includeone or more of power cycling handheld relay device 200, powering offhandheld relay device 200, resetting handheld relay device 200 tofactory default settings and outputting a visual notification to thedisplay 222 of handheld relay device. If no failure conditions aredetermined, the routine can return to Step 362 to continue monitoringfor failure conditions at a first rigor.

Monitoring and alarm routines 450 can also be stored in a memory 325,330 and executed by one or more processors 324 of the one or more readerdevices 120. Referring again to FIG. 3 , at Step 452, reader device 120is initialized, for example, by powering on or power cycling the device.At Step 454, reader device 120 periodically performs a check to confirmthat it has received data from the handheld relay device 200, which caninclude, for example, data indicative of a sensed analyte level. At Step456, the monitoring routine can also determine if a command to output analarm has been received from the handheld relay device 200, aspreviously described at Step 358. If an alarm command is received, thenthe reader device 120 can output an alarm at Step 460. If an alarmcommand has not been received, then at Step 458, the reader device 120checks for the occurrence of one or more predetermined alarm conditions,which may comprise any of the alarm conditions described above withrespect to the handheld relay device 200. If an alarm condition isdetected, then the reader device 120 can output an alarm at Step 460. Ifan alarm condition is not detected, then the reader device can output anindication to the display 122 that the current status is normal, or inthe alternative, take no action and return to Step 456 to continuemonitoring for alarm commands and conditions.

In further embodiments, the reader device 120 can concurrently execute,by its one or more processors 324, instructions stored in memory 325,330 for the monitoring of failure conditions. At Step 464, reader device120 can periodically perform checks for one or more predeterminedfailure conditions at a second rigor. As described earlier, in someembodiments, the degree of rigor for failure condition monitoring in thereader device 120 is lower than the degree of rigor for failurecondition monitoring in the handheld relay device 200. At Step 466, thereader device 120 determines if one or more predetermined failureconditions has occurred. If so, the reader device 120 can perform one ormore fail-safe procedures at Step 468. It should be understood that thepredetermined failure conditions and fail-safe procedures in the readerdevice 120 can include one or more of the same failure conditions andfail-safe procedures described above with respect to the handheld relaydevice 200. If no failure conditions are determined, the routine canreturn to Step 464 to continue monitoring for failure conditions at asecond rigor.

In certain embodiments, reader device 120 can also be configured tostore and retrieve data indicative of a sensed analyte level and invitro blood analyte measurements, for the creation of reports. Forexample, a user of reader device 120 can use a user interface to choosea report from a plurality of selectable report formats. One or moreprocessors 324 of reader device 120 can then retrieve at least a subsetof the data indicative of the sensed analyte level and the in vitroblood analyte measurements based on the user's selection, organize theretrieved data, and output the selected report to display 122 of readerdevice 120.

Example Embodiments of Sensor Control Devices

FIGS. 2C-D are block schematic diagrams depicting example embodiments ofsensor control device 102 having analyte sensor 104 and sensorelectronics 160 (including analyte monitoring circuitry) that can havethe majority of the processing capability for rendering end-result datasuitable for display to the user. In FIG. 2C, a single semiconductorchip 161 is depicted that can be a custom application specificintegrated circuit (ASIC). Shown within ASIC 161 are certain high-levelfunctional units, including an analog front end (AFE) 162, powermanagement (or control) circuitry 164, processor 166, and communicationcircuitry 168 (which can be implemented as a transmitter, receiver,transceiver, passive circuit, or otherwise according to thecommunication protocol). In this embodiment, both AFE 162 and processor166 are used as analyte monitoring circuitry, but in other embodimentseither circuit can perform the analyte monitoring function. Processor166 can include one or more processors, microprocessors, controllers,and/or microcontrollers, each of which can be a discrete chip ordistributed amongst (and a portion of) a number of different chips.

A memory 163 is also included within ASIC 161 and can be shared by thevarious functional units present within ASIC 161, or can be distributedamongst two or more of them. Memory 163 can also be a separate chip.Memory 163 can be volatile and/or non-volatile memory. In thisembodiment, ASIC 161 is coupled with power source 170, which can be acoin cell battery, or the like. AFE 162 interfaces with in vivo analytesensor 104 and receives measurement data therefrom and outputs the datato processor 166 in digital form, which in turn processes the data toarrive at the end-result glucose discrete and trend values, etc. Thisdata can then be provided to communication circuitry 168 for sending, byway of antenna 171, to handheld relay device 200 (not shown), forexample, where minimal further processing is needed by the residentsoftware application to display the data.

FIG. 2D is similar to FIG. 2C but instead includes two discretesemiconductor chips 162 and 174, which can be packaged together orseparately. Here, AFE 162 is resident on ASIC 161. Processor 166 isintegrated with power management circuitry 164 and communicationcircuitry 168 on chip 174. AFE 162 includes memory 163 and chip 174includes memory 165, which can be isolated or distributed within. In oneexample embodiment, AFE 162 is combined with power management circuitry164 and processor 166 on one chip, while communication circuitry 168 ison a separate chip. In another example embodiment, both AFE 162 andcommunication circuitry 168 are on one chip, and processor 166 and powermanagement circuitry 164 are on another chip. It should be noted thatother chip combinations are possible, including three or more chips,each bearing responsibility for the separate functions described, orsharing one or more functions for fail-safe redundancy.

Performance of the data processing functions within the electronics ofthe sensor control device 102 provides the flexibility for systems 100Aand 100B to schedule communication from sensor control device 102 to oneor more reader devices 120 or handheld relay device 200, which in turnlimits the number of unnecessary communications and can provide furtherpower savings at sensor control device 102.

Information may be communicated from sensor control device 102 to one ormore reader devices 120 or handheld relay device 200 automaticallyand/or continuously when the analyte information is available, or maynot be communicated automatically and/or continuously, but rather storedor logged in a memory of sensor control device 102, e.g., for lateroutput. In another embodiment, information, including data indicative ofa sensed analyte level, may be stored or logged in a memory of handheldrelay device 200 and/or one or more reader devices 120. Accordingly, inmany embodiments of systems 100A and 100B, analyte information derivedby sensor control device 102 is made available in a user-usable orviewable form only when queried by the user such that the timing of datacommunication is selected by the user.

Data can be sent from sensor control device 102 to handheld relay device200 and/or one or more reader devices 120 at the initiative of eithersensor control device 102, handheld relay device 200 or one or morereader devices 120. For example, in some example embodiments sensorcontrol device 102 can communicate data periodically in a broadcast-typefashion, such that an eligible handheld relay device 200, if in rangeand in a listening state, can receive the communicated data (e.g.,sensed analyte data). This is at the initiative of sensor control device102 because handheld relay device 200 does not have to send a request orother transmission that first prompts sensor control device 102 tocommunicate. Broadcasts can be performed, for example, using an activeWi-Fi, Bluetooth, or BTLE connection. The broadcasts can occur accordingto a schedule that is programmed within sensor control device 102 (e.g.,about every 1 minute, about every 5 minutes, about every 10 minutes, orthe like). Broadcasts can also occur in a random or pseudorandomfashion, such as whenever sensor control device 102 detects a change inthe sensed analyte data. Further, broadcasts can occur in a repeatedfashion regardless of whether each broadcast is actually received byhandheld relay device 200.

Systems 100A and 100B can also be configured such that the handheldrelay device 200 sends a transmission that prompts sensor control device102 to communicate its data to the handheld relay device 200. Similarly,systems 100A and 100B can also be configured such that one or morereader devices 120 send a transmission that prompts handheld relaydevice 200 to communicate its data to the one or more reader devices120. This is generally referred to as “on-demand” data transfer. Anon-demand data transfer can be initiated based on a schedule stored inthe memory of the handheld relay device 200 or the one or more readerdevices 120, or at the behest of the user via a user interface of thehandheld relay device 200 or the one or more reader devices 120. Forexample, if the user wants to check his or her analyte level, the usercould perform a scan of sensor control device 102 using an NFC,Bluetooth, BTLE, proprietary protocol or Wi-Fi connection. Data exchangecan be accomplished using broadcasts only, on-demand transfers only, orany combination thereof.

Accordingly, once a sensor control device 102 is placed on the body sothat at least a portion of sensor 104 is in contact with the bodilyfluid and electrically coupled to the electronics within device 102,sensor derived analyte information may be communicated in on-demand orbroadcast fashion from sensor control device 102 to handheld relaydevice 200 or one or more reader devices 120. On-demand transfer canoccur by first powering on handheld relay device 200 or one or morereader devices 120 (or they may be continually powered) and executing asoftware algorithm stored in and accessed from a memory of handheldrelay device 200 or one or more reader devices 120 to generate one ormore requests, commands, control signals, or data packets to send tosensor control device 102. The software algorithm executed under, forexample, the control of processing hardware 257 of handheld relay device200 may include routines to detect the position of the sensor controldevice 102 relative to handheld relay device 200 to initiate thetransmission of the generated request command, control signal and/ordata packet.

Different types and/or forms and/or amounts of information may be sentas part of each on-demand or other transmission including, but notlimited to, one or more of current analyte level information (i.e., realtime or the most recently obtained analyte level information temporallycorresponding to the time the reading is initiated), rate of change ofan analyte over a predetermined time period, rate of the rate of changeof an analyte (acceleration in the rate of change), or historicalanalyte information corresponding to analyte information obtained priorto a given reading and stored in a memory of sensor control device 102.

Some or all of real time, historical, rate of change, rate of rate ofchange (such as acceleration or deceleration) information may be sent tohandheld relay device 200 or one or more reader devices 120 in a givencommunication or transmission. In certain embodiments, the type and/orform and/or amount of information sent to handheld relay device 200 orone or more reader devices 120 may be preprogrammed and/or unchangeable(e.g., preset at manufacturing), or may not be preprogrammed and/orunchangeable so that it may be selectable and/or changeable in the fieldone or more times (e.g., by activating a switch of the system, etc.).Accordingly, in certain embodiments, handheld relay device 200 or one ormore reader device 120 can output a current (real time) sensor-derivedanalyte value (e.g., in numerical format), a current rate of analytechange (e.g., in the form of an analyte rate indicator such as an arrowpointing in a direction to indicate the current rate), and analyte trendhistory data based on sensor readings acquired by and stored in memoryof sensor control device 102 (e.g., in the form of a graphical trace).Additionally, an on-skin or sensor temperature reading or measurementmay be communicated from sensor control device 102 with each datacommunication. The temperature reading or measurement, however, may beused in conjunction with a software routine executed by handheld relaydevice 200 to correct or compensate the analyte measurement output tothe user by handheld relay device 200, instead of or in addition toactually displaying the temperature measurement to the user.

U.S. Patent Publ. No. 2011/0213225 (the '225 Publication) generallydescribes components of an in vivo-based analyte monitoring system thatare suitable for use with the authentication methods and hardwareembodiments described herein. The '225 Publication is incorporated byreference herein in its entirety for all purposes. For other examples ofsensor control device 102 and reader device 120, see, e.g., devices 102and 120, respectively, as described in the incorporated '225Publication.

Additional detailed description of the analyte monitoring system, andits various components including the functional descriptions of thetransceivers are provided in U.S. Pat. No. 6,175,752 issued Jan. 16,2001, entitled “Analyte Monitoring Device and Methods of Use”, and inU.S. patent application Ser. No. 10/745,878 filed Dec. 26, 2003, nowU.S. Pat. No. 7,811,231, entitled “Continuous Glucose Monitoring Systemand Methods of Use”, each assigned to the Assignee of the presentapplication, and each of which are incorporated herein by reference forall purposes.

Example Embodiments for Wireless Communication in In Vivo AnalyteMonitoring Systems

In all of the embodiments described herein, communications betweensensor control device 102 and handheld relay device 200 (as shown inFIG. 1B), can occur wirelessly using a Bluetooth, Bluetooth Low Energy(BTLE) or proprietary wireless protocol. Communications between handheldrelay device 200 and reader device 120 (as shown in FIG. 1B), or betweensensor control device 102 and reader device 120 (as shown in FIG. 1A),can occur wirelessly using a Bluetooth or Bluetooth Low Energy (BTLE)standard protocol. Further described below are example embodiments ofBluetooth and BTLE topologies and advertising schemes for use with invivo analyte monitoring systems, like those described above and depictedin FIGS. 1A and 1B.

FIGS. 4A and 4B are diagrams showing example topologies for use with invivo analyte monitoring systems, in which one or more devicescommunicate through a Bluetooth or BTLE protocol. Bluetooth and BTLEdevices can communicate with each other in a piconet, which can comprisetwo or more devices occupying the same channel (or different channels),and synchronized to a common clock. FIG. 4A depicts an exampleembodiment of a BTLE topology with sensor control device 102, handheldrelay device 200, and reader devices 120 configured as a single BTLEpiconet 410 comprising three channels 412, 414, and 416. In thisembodiment, sensor control device 102 can be configured as a slavedevice (S1) relative to handheld relay device 200, and handheld relaydevice 200 can be configured as a master device (M1) relative to sensorcontrol device 102. Reader devices 120 can each be configured as masterdevices (M2, M3) relative to handheld relay device 200, and handheldrelay device 200 can be configured as a slave device (S2, S3) to readerdevices 120.

Furthermore, in this embodiment, sensor control device 102 cancommunicate with handheld relay device 200 over an advertising channelor a piconet physical channel. For example, the wireless communicationcircuitry of sensor control device 102 can be configured to transmitdata according to a plurality of connection parameters, including aconnection interval maximum parameter, a slave latency parameter, and asupervision timeout parameter. In one embodiment, the connectioninterval maximum parameter can be set to a value equal to or less than 2seconds, between 2 and 4 seconds, or equal to or greater than 4 seconds.The supervision timeout parameter can also be set to a value equal to orless than 6 seconds, or greater than 6 seconds. Similarly, handheldrelay device 200 and reader devices 120 can communicate with each otherover different advertising channels or different piconet physicalchannels, either concurrently or non-concurrently, so as to avoid datacollision. While FIG. 4A depicts two reader devices 120, the embodimentcan include any number of similar or dissimilar reader devices 120,including one device, three devices, four devices or more. Additionally,while FIG. 4A shows handheld relay device 200 as a centralized “hub” ofthe communication topology, a reader device 120, remote terminal 170 orother computer device capable of wireless communications can also beused in its place.

FIG. 4B depicts an alternative embodiment of a BTLE topology, withsensor control device 102, handheld relay device 200, and reader devices120 configured as a BTLE scatternet 420, which comprises piconets 422,424, and 426, wherein each piconet comprises a separate channel. In thisembodiment, sensor control device 102 is configured as a slave device(S1) relative to handheld relay device 200, and handheld relay device200 is configured as a master device (M1) relative to sensor controldevice. Reader devices 120 are each configured as slave devices (S2, S3)relative to handheld relay device 200, and handheld relay device isconfigured as a master device (M2, M3) relative to each reader device120.

As with the prior embodiment, sensor control device 102 can communicatewith handheld relay device 200 over an advertising channel or a piconetphysical channel. Likewise, the wireless communication circuitry ofsensor control device 102 can be configured to transmit data inaccordance with the multiple connection parameters and options describedwith respect to topology 410 (FIG. 4A). Furthermore, in someembodiments, sensor control device 102 can be configured to operate in adiscoverable state relative to the handheld relay device 200. Thehandheld relay device 200 can also be configured to operate in adiscoverable state relative to one or more reader devices 120. Inaddition, one or more reader devices 120 may be configured to operate ina discoverable state relative to handheld relay device 200.

In still other embodiments of BTLE topologies (not shown), sensorcontrol device 102 can be configured as a master device relative tohandheld relay device 200, and handheld relay device can be configuredas a slave device relative to sensor control device 102. Similarly,reader devices 120 can each be configured relative to handheld relaydevice 200 as described with respect to either FIG. 4A or 4B. That is,reader devices 120 can serve as either master or slave devices relativeto handheld relay device 200, and vice versa.

FIGS. 5A and 5B are timeline diagrams showing certain embodiments ofBluetooth and BTLE advertising schemes for use with in vivo analytemonitoring systems, as described above and depicted in FIGS. 1A, 1B, 4Aand 4B. As described earlier, in recent years, the threat ofunauthorized tracking of wireless devices has become a greater concern.For example, third parties may surreptitiously operate wireless device“trackers” at various geographical locations, which can then be used totrack the movement of an individual based on a unique address of awireless device carried by the individual. While certain wirelesscommunication standard protocols have implemented countermeasuresagainst such “trackers,” these countermeasures may be inadequate. Forexample, in accordance with the Bluetooth and BTLE standard protocols,wireless devices can be configured to periodically generate randomaddresses or resolvable addresses, which can be used to obscure the trueidentity of a wireless device and prevent it from being tracked.However, “trackers” have become more sophisticated and can associate twoor more randomly generated addresses with a particular wireless device.In particular, a “tracker” may observe a sequence of events in which afirst device address disappears, followed by the appearance of a seconddevice address. By analyzing the timing of such events, a “tracker” candeduce that the two device addresses actually correlate to a singlewireless device that has replaced an old device address with a newdevice address.

FIG. 5A is a timeline diagram depicting an embodiment of a BTLEadvertising scheme that can be used to resist efforts to track a sensorcontrol device 102, handheld relay device 200, or reader device 200 ofthe previously described in vivo analyte monitoring systems. In oneexample, the wireless communication circuitry of sensor control device102 begins transmitting a first set of advertisement packets (AE1) attime, T1, each having a first address. The advertisement packets aretransmitted periodically at a first rate (AR1) for a first predeterminedperiod of time (P1). The first address can be a randomly generatedaddress. Similarly, the first rate (AR1) and the first predeterminedperiod of time (P1) can be based at least in part on a randomlygenerated number.

Referring still to FIG. 5A, at time, T2, sensor control device 102begins transmitting a second set of advertisement packets (AE2), whereineach packet has a second address. The second set of advertisementpackets are transmitted periodically at a second rate (AR2) for a secondpredetermined period of time (P2). The second address (AE2) can bedifferent from the first address (AE1), and can also be a randomlygenerated address. Similarly, the second rate (AR2) can be differentfrom the first rate (AR1), and can also be based in part on a randomlygenerated number. The second predetermined period of time (P2) can bedifferent from the first predetermined period of time (P1), and can alsobe based at least in part on a randomly generated number. At time, T3,the first predetermined period of time (P1) ends, and sensor controldevice 102 ceases to transmit the first set of advertisement packets(AE1). Sensor control device 102 continues to transmit the second set ofadvertisement packets (AE2) until time, T4, when the secondpredetermined period of time (P2) ends.

As shown by the shaded area of FIG. 5A, the advertising scheme includesan overlapping period of time (Ov1) in which the first and secondpredetermined periods of time (P1, P2) are overlapping. The duration ofthe overlapping period of time (Ov1) can be based at least in part on arandomly generated number. In this regard, a tracker would be unable toassociate the first address and second address with sensor controldevice 102 based on the timing, initiation and cessation of the firstand second advertisement packets.

FIG. 5B is a timeline diagram depicting another example embodiment of aBTLE advertising scheme that can be used to counteract efforts to tracka sensor control device 102, handheld relay device 200, or reader device120 of the previously described in vivo analyte monitoring systems. Theembodiment shown in FIG. 5B is similar to that of FIG. 5A, except that athird set of advertisement packets (AE3) are additionally transmitted attime, T4, each having a third address. The third set of advertisementpackets (AE3) is transmitted periodically at a third rate (AR3) for athird predetermined period of time (P3). The third address can be arandomly generated address. Similarly, the third rate (AR3) and thirdpredetermined period of time (P3) can be based at least in part on arandomly generated number.

Referring still to FIG. 5B, at time, T5, the second predetermined periodof time (P2) ends, and sensor control device 102 ceases to transmit thesecond set of advertisement packets (AE2). The third address can bedifferent from the first and second addresses. The third rate (AR3) canbe different from the first and second rates (AR1, AR2), and the thirdpredetermined period of time (P3) can be also be different from thefirst and second predetermined periods of time (P1, P2). Sensor controldevice 102 continues to transmit the third set of advertisement packets(AE3) until time, T6, when the third predetermined period of time (P3)ends.

As shown by the shaded areas of FIG. 5B, the advertising schemes includetwo separate overlapping periods of time (Ov1, Ov2), wherein the firstand second predetermined periods of time (P1, P2) are overlapping andthe second and third predetermined periods of time (P2, P3) areoverlapping. The duration of the second overlapping period of time (Ov2)can be based at least in part on a randomly generated number. As withthe previous embodiment, a tracker would be unable to associate thefirst, second and third addresses with sensor control device 102 basedon the timing, initiation and cessation of the first, second and thirdadvertisement packets.

In the advertising scheme shown in FIG. 5B, the first and thirdpredetermined periods of time (P1, P3) do not overlap with each other.It should be understood, however, that the advertising scheme can beconfigured such that the first and third predetermined periods of time(P1, P3) also overlap with each other, in addition to each overlappingwith the second predetermined period of time (P2). Moreover, it shouldalso be understood that the advertising schemes disclosed herein canalso be configured such that any number of predetermined time periods(e.g., P1, P2, P3 and so on) can be either partially overlapping orcompletely overlapping.

In the embodiments described above, any or all of the first, second andthird addresses can be 48-bit addresses, in accordance with theBluetooth and BTLE standard protocols. Further, any or all of the first,second and third addresses can be generated by the one or moreprocessors 166 of sensor control device 102 at the advent of apredetermined period of time. In an alternative embodiment, theaddresses can be generated at other times such as, for example, duringthe manufacture of sensor control device 102, when sensor control device102 is powered on (or power cycled), due to a change in geographicallocation of sensor control device 102, or at any other time prior to theadvent of a predetermined period of time. In yet another embodiment, theaddresses can be generated based on the expiration of a timer routineexecuted by sensor control device 102. Generated addresses can then bestored in memory 163, 165 of sensor control device 102 and laterretrieved prior to the advent of a predetermined period of time.

In further embodiments of advertising schemes, any or all of the first,second and third addresses can be resolvable addresses. In accordancewith the Bluetooth and BTLE standard protocol, for example, a resolvableaddress can have a first portion of an address which is randomlygenerated, and a second portion of the address which can be resolvedusing an identity resolution key (IRK). The identity resolution key canbe a shared secret, which can be stored in and retrieved from the memory163, 165 of sensor control device 102, the memory 280 of handheld relaydevice 200, the memory 323, 325 of one or more reader devices 120, or ina trusted computer system 180 accessible via a network 190.

FIG. 5C is a flowchart diagram showing an example method in which readerdevice 120 attempts to determine identity of sensor control device 102based on a first advertisement packet containing a resolvable address,as described in the above embodiments. Before describing the steps, itshould be understood that one or more identity resolution keys (IRKs)can be generated by either sensor control device 102 or reader device120, and exchanged during a pairing process. One or more IRKs can bestored in a memory 163, 165 of the sensor control device 102 and amemory 323, 325 of the reader device 120. In an alternative embodiment,one or more IRKs can be stored in a trusted computer system 180 forlater retrieval by reader device 120, for example. It should also beunderstood that although the described method refers to reader device120 as a device that can resolve the address of the sensor controldevice 102, the same method can be utilized by the handheld relay device200 described in prior embodiments and depicted in FIGS. 1B and 2B.

Turning to FIG. 5C, at Step 572, a reader device 120 receives and storesthe IRK during a pairing procedure with sensor control device 102. Inanother embodiment, for example, the reader device 120 can receive oneor more IRKs from a trusted computer system 180 over a network 190,during a manufacturing process of reader device 120, or through anyother means of communication. At Step 574, reader device 120 receives afirst advertisement packet, similar to the ones described above anddepicted in FIGS. 5A and 5B. The first advertisement packet includes afirst address that is resolvable. At Step 576, reader device 120extracts a first portion of the first advertisement packet. Theextracted portion can comprise a 24-bit random part (prand). At Step578, reader device 120 retrieves an IRK and generates a hash value basedon the IRK. For example, a random address hash function, stored in amemory of the reader device 120, can be performed on the extractedportion (prand) of the first advertisement packet to generate a localhash value. At Step 580, reader device 120 compares the generated hashvalue (or local hash value) with a second extracted portion of theadvertisement packet. For example, the second extracted portion of theadvertisement packet can be a 24-bit hash value. At Step 582, if thereis a match between the generated hash value (or local hash value) andthe second extracted portion, then, at Step 590, reader device 120 isable to resolve the address of sensor control device 102 and determineits identity. If there is not a match, at Step 584, reader device 120determines if there are any additional IRKs available for retrieval. Ifso, at Step 586, reader device 120 retrieves the next IRK and performsSteps 578, 580 and 582 in an attempt to resolve the address of sensorcontrol device 102 using the next available IRK. If no remaining IRKsare available, the process ends at Step 588, and the reader device 120is unable to resolve the address of sensor control device 102.

The steps in the flowchart of FIG. 5C can be used for any advertisementpacket containing a resolvable address, including, for example, thesecond and third sets of advertisement packets described above anddepicted in FIGS. 5A and 5B.

In all of the embodiments described herein, communication can occurbetween sensor control device 102 and reader device 120 and/or handheldrelay device 200 using a Bluetooth or BTLE protocol. In every instancewhere communication between devices 102, 120 and 200 is to occur, apaired connection can be established between two devices as set forth inthe Bluetooth and BTLE standard protocols. However, significant timegaps can exist between the sending of communications between devices 102and 120 (or 200) and the maintenance of a paired connection, as well asthe handshaking required for bringing up and tearing down pairedconnections, can require significant energy consumption by devices 102and 120 (or 200). This is particularly problematic with sensor controldevice 102, which typically has a small battery with a low power budget.

Therefore, to conserve power, sensor control device 102 can beprogrammed to transmit data within the payload section of a typicaladvertisement packet (or channel) pursuant to the Bluetooth or BTLEstandard protocols. Likewise, reader device 120 and/or handheld relaydevice 200 can be programmed to extract this data from the payloadsection of the advertisement packet.

The data within the advertising packet can be any data desired fortransmission from sensor control device 102. One example is dataindicative of the user sensed analyte level. This data can be encryptedto maintain confidentiality and for integration within any and all ofthe authentication schemes described herein. For example, communicationssent from sensor control device 102, can be a BTLE advertising packetcontaining the encrypted analyte data 324 within the payload section ofthat advertising packet.

FIG. 6A is a block diagram depicting an example embodiment of a BTLEadvertising packet 602, having a preamble 603, an access address 604(which together form a header section), a protocol data unit (PDU) 605,and a cyclic redundancy check (CRC) 606. In this embodiment, advertisingpacket 602 is a connectable undirected advertising packet type, however,packet 602 can be other types as well including a connectable directedadvertising packet type, a non-connectable undirected advertising packettype, or a scannable undirected advertising packet type.

Within PDU 605 is an advertising header section 608 and an advertisingpayload section 610, as shown in FIG. 6B. The encrypted analyte data 324is stored within advertising payload section 610. The encrypted datashould be smaller than the maximum payload of the advertising packet,although analyte data that is too large can be split across subsequentadvertising packets if desired. Various amounts of data can be includedin the advertising packet. In one embodiment, the BTLE protocol allows22 bytes of payload to be included in an advertising packet, and thusthe encrypted data is 22 bytes or less in size. (FIG. 6B shows some ofthe total available payload as unused.) Encryption schemes such asAES128 use a 16 byte block size, which can be accommodated within theadvertising payload. Depending on the size of the measurement data for asingle sensing of analyte level, at least one analyte level measurementcan fit within the 16 byte encrypted block. In some embodiments, thedata for two or three (or more) analyte level measurements will fitwithin the 16 byte encrypted block. In those embodiments, sensor controldevice 102 can be programmed to insert the two or three (or more) mostrecent analyte level measurements into each 16 byte encrypted block.Reader device 120 or handheld relay device 200 can then reconstruct therecent analyte level trends for the user, i.e., both current and limitedhistorical analyte data, in case one or more prior measurements were notsuccessfully transmitted by sensor control device 102 or received byreader device 120 or handheld relay device 200.

The period between subsequent advertising transmissions from sensorcontrol device 102 can be set as desired. For example, the intervalbetween the transmission of advertising packets can be one minute, twominutes, five minutes, 10 minutes, 15 minutes, one hour, and so forth.Furthermore, this interval can be variable so as to accommodate theuser's preferences or conserve battery life, etc.

In embodiments that utilize this advertising packet approach, sensorcontrol device 102 and reader device 120 (or handheld relay device 200)can first establish a typical paired connection pursuant to theBluetooth or BTLE standard protocols. This will allow the devices tobecome bonded so that each will recognize the other and will onlyconduct communications with the other. While this paired connection isestablished, devices 102 and 120 (or 200) can exchange information so asto create any of the authentication regimes described herein. Forexample, device 102 can transmit an identifier. In some embodiments,communication between multiple sensor control devices and one readerdevice (or one handheld relay device), or communication between multiplereader devices (or handheld relay devices) and one sensor control deviceis permitted. This is described in greater detail within U.S. PatentApplication Ser. No. 62/001,343, filed May 21, 2014, which isincorporated by reference herein in its entirety for all purposes.

When using the advertising packets, sensor control device 102 will becommunicating in a unidirectional manner, with analyte data transmittedon a scheduled basis without prompting by reader device 120. Shouldreader device 120 need to transmit to sensor control device 102, then apaired connection can be created.

Also provided herein are example embodiments of devices (and methods ofoperating the same) having a test strip interface that can be activatedupon insertion of a test strip. These devices can include handheld relaydevice 200, reader device 120, and/or an in vitro analyte meter. Thesedevices can be kept in a power-off state, or a relatively low power(e.g., sleep) state, to minimize current draw from the power supply andmaximize operating life. Upon insertion of a test strip, the devicehardware and/or software can cause the device to exit the power-off (orlow-power) state and enter a power-on (or relatively higher power) statefor regular operation.

FIG. 7A is a block diagram depicting an example embodiment of handheldrelay device 200 with power latch (or connection) circuitry 702. Here,power latch circuitry 702 is electrically coupled with test strip port706, power supply 256, and power distribution node 710 (e.g., a powerplane). Test strip port 706 is also coupled to a reference node 701(e.g., ground) and is configured to output an analog signal indicativeof an analyte level in a sample on test strip 704 to analog front end(AFE) circuitry 708, which can include conditioning circuitry (e.g., anoperational amplifier) that conditions the analog signal for conversionto digital form by an A/D converter (not shown) that can be, forexample, in AFE 708 or in back end electronic circuitry 712. Test stripport 706 and AFE 708 can form test strip interface 224. Back endelectronic circuitry 712, can include one or more processors 257 as wellas one or more other components shown in FIG. 2B (e.g., memory 280, RFtransceiver 252, multi-functional circuitry 252, etc.). Back endcircuitry 712 can be coupled with RF antenna 251, an optional secondaryswitch 714, and output unit 260, which is in turn coupled with display222.

Power latch circuitry 702 can be configured to sense or detect theinsertion of test strip 704 into test strip port 706 and, in response,connect power supply 256 to an electrical load, which can include all orpart of the remaining circuitry within relay device 200. Power latchcircuitry 702 can also be configured to maintain the connection of powersupply 256 after test strip 704 is removed, and to continue to maintainthe connection until instructed to disconnect, such as by processor 257.In this manner, relay device 200 can be kept in the power-off (or arelatively low power) state until needed by the user to perform ananalyte measurement with test strip 704. Although described with respectto handheld relay device 200, these methods and circuits can likewise beimplemented in embodiments of other devices having a test stripinterface such as reader device 120 or an in vitro meter.

In FIG. 7A, test strip 704 can include a conductive region 705 on afirst end that is inserted into test strip port 706. The conductiveregion 705 can include, for example, one or more conductive traces orbars that electrically connect contacts in test strip port 706 andcreate a closed circuit (e.g., a short) to reference node 701 (see alsoFIG. 7B). Power latch circuit 702 can sense or detect this connection toreference node 701 and subsequently connect power supply 256 (e.g., arechargeable battery, a coin cell battery, or otherwise) to the device'spower node 710. This power connection supplies power to each of theother circuits within device 200 that are coupled to power node 710 andallows these circuits to initiate operation or exit low-power sleepstates and transition to a relatively higher power state, such as apower-on state.

FIG. 7B is a schematic diagram depicting an example embodiment of powerlatch circuitry 702 and its connections in greater detail. Here, powerlatch circuitry 702 includes a first transistor Q1 coupled with a secondtransistor Q2. In this embodiment, Q1 is a p-channel enhanced MOSFET andQ2 is an n-channel enhanced MOSFET, although other types of field effecttransistors (FETs) can be used as well, with modifications as will beapparent to those of ordinary skill in the art. Those other transistortypes can include, but are not limited to, JFET, MOSFET without bulk,MOSFET depleted, MESFET, or IGFET. Processes with low gate leakages andlow drain-source leakages are particularly suitable for use with thecontrol circuit embodiments described herein.

The drain of Q1 is connected to power node 710 and the source of Q1 isconnected to power source 256 and a first end of resistor R1. The secondend of R1 is connected to the gate of Q1, the drain of Q2, and a firstend of resistor R2 (represented by node 720). The source of Q2 isconnected to reference node 701 and the gate of Q2 is connected to afirst end of resistor R3 and node 722, which can receive a signal fromprocessor 257. Resistor R3 is coupled between the gate of Q2 andreference node 701.

Test strip port 706 communicates with AFE 708 through node 724. Thepotential connection of conductive region 705 with correspondingcontacts within test strip port 706 is visualized here as a switch 707.(In other embodiments, the insertion of strip 704 can trigger an actualswitch to signal insertion.) In this embodiment, insertion of strip 704effectively closes switch 707, and connects one end of R2 to reference(ground) node 701 and pulls node 720 low, which biases the gate of Q1towards a low voltage (e.g., a digital “0”). This activates Q1 (e.g.,allows current to flow across the drain and source) and connects powersupply 256 to power distribution node 710. Each circuit connected topower node 710 can then draw current from supply 256, including back endelectronics 712 and processor 257. Processor 257 can then enter itspower-on (or relatively high power) state, perform an initializationroutine if necessary, and generate a latch signal at node 722.

The latch signal at node 722 is a high voltage signal in this embodiment(e.g., a digital “1”) and activates Q2, which in turn further biasesnode 720 towards a low voltage. At this point, circuit 702 can bemaintained in its power-supply connected state, such that removal ofstrip 704 (and opening of switch 707) will not disconnect power supply256 from power node 710. Although not shown, a user accessible switchcan also be coupled between node 720 and ground, such that the user cancause connection of supply 256 and activate device 200 without theinsertion of strip 704.

In many embodiments R1 is chosen to have a value greater than R2. A highvalue for R1 minimizes leakage current through Q2. R3 assists in pullingnode 722 towards the low voltage of reference node 701 when processor257 is disconnected, to prevent inadvertent activation of Q2. Theembodiment of FIG. 7B is described as functioning with signals ofvarious voltage polarities (e.g., high and low), but those polaritiesare used only as an example and the same or similar functionality can beachieved by implementing circuit 702 to operate with polarity levelsopposite to those described here.

After being activated, handheld relay device 200 can perform varioustasks. Wireless communication circuitry of relay device 200 can transmitan attempt to establish a communication link with another device (e.g.,sensor control device 102 or reader device 120), for example, byinitiating the transmission of an advertising signal according to aBluetooth or BTLE protocol, and negotiate establishment of the wirelesslink. This can occur directly as a result of connection of the powersupply to the wireless communication circuitry (through node 710), orindirectly as a result of processing circuitry 257 instructing orotherwise causing the wireless communication circuitry to transmit theattempt.

Relay device 200 can also begin the steps to conduct a samplemeasurement, such as by notifying (audibly, visually, through vibration,etc.) the user to dose strip 704, monitoring for strip fill, notifyingthe user when enough blood has been applied, performing the analytemeasurement, displaying the result, and communicating the results toanother device (e.g., to sensor control device 102 for calibration or toreader device 120). In some embodiments, relay device 200 does notinclude a graphical display, or lacks a display altogether, and uponestablishing the connection, reader device 120 is used as the userinterface to communicate with the user and control (or assist incontrolling) the execution of the various sample measurement steps, andthen display the measurement results.

Processor 257 maintains control over latch circuit 702 via the latchingsignal applied to node 722. Processor 257, executing instructions frommemory, can disconnect power supply 256 by changing the polarity of thelatching signal at node 722 from high to low. For example, processor 257can have a “time-out” function and can monitor the amount of time that,for example, has passed since insertion of strip 704, since completionof the measurement, since display of the results, or since the last useraction was taken, and upon reaching a maximum time duration of time,then change the polarity of the latching signal to disconnect supply256.

Referring back to FIG. 7A, optional switch 714 is coupled with back endelectronics 712 and can be used to reset device 200. For example, if thecommunication link (e.g., BTLE) between relay device 200 and anotherdevice is lost, then the user can use switch 714 to reset back endelectronics 712 (or a sub-component thereof, such as processor 257 orthe communication circuitry) to reestablish the communication link.

The embodiments described with respect to FIGS. 7A and 7B can offer anumber of improvements over conventional devices. For example, one suchimprovement is the increase in operating life achieved by enablingdevice activation upon insertion of a test strip, and by enabling devicedeactivation upon removal of the test strip or subsequently thereafterunder the control of processing circuitry or a timer. The increase inoperating life can be achieved by minimizing the draw of current fromthe power supply to only those times when the device is in use, and bykeeping all or a majority of the device circuitry in the power-off (orlow power) state during those times when the device is not being used.

In many instances, entities are described herein as being coupled toother entities. The terms “coupled” and “connected” (or any of theirforms) are used interchangeably herein and, in both cases, are genericto the direct coupling of two entities (without any non-negligible(e.g., parasitic) intervening entities) and the indirect coupling of twoentities (with one or more non-negligible intervening entities). Whereentities are shown as being directly coupled together, or described ascoupled together without description of any intervening entity, thoseentities can be indirectly coupled together as well unless the contextclearly dictates otherwise.

While the embodiments are susceptible to various modifications andalternative forms, specific examples thereof have been shown in thedrawings and are herein described in detail. It should be understood,however, that these embodiments are not to be limited to the particularform disclosed, but to the contrary, these embodiments are to cover allmodifications, equivalents, and alternatives falling within the spiritof the disclosure. Furthermore, any features, functions, steps, orelements of the embodiments may be recited in or added to the claims, aswell as negative limitations that define the inventive scope of theclaims by features, functions, steps, or elements that are not withinthat scope.

1-259. (canceled)
 2. A method for advertising a sensor control device inan in vivo analyte monitoring system, the method comprising: generatinga first address associated with the sensor control device; transmittingperiodically, at a first advertising rate for a first predeterminedperiod, one or more first advertisement packets comprising the firstaddress; generating a second address associated with the sensor controldevice, wherein the first address is different from the second address;and transmitting periodically, at a second advertising rate for a secondpredetermined period, one or more second advertisement packetscomprising the second address, wherein the first predetermined periodoverlaps with the second predetermined period; and wherein thetransmitting steps comprise wirelessly transmitting the advertisementpackets using one of a near field communication (NFC) protocol, a RFIDprotocol, a Bluetooth or Bluetooth Low Energy protocol, a Wi-Fiprotocol, or a proprietary protocol.
 3. The method of claim 2, whereinthe first advertising rate is different from the second advertisingrate.
 4. The method of claim 2, wherein either or both of the firstadvertising rate and the second advertising rate is based at least inpart on a randomly generated number.
 5. The method of claim 2, whereinthe duration of the overlap between the first predetermined period andthe second predetermined period is based at least in part on a randomlygenerated number.
 6. The method of claim 2, wherein either or both ofthe first address and the second address is a randomly generatedaddress.
 7. The method of claim 2, wherein at least one of the firstaddress or the second address is a resolvable address, wherein theresolvable address is adapted to be resolved to an address associatedwith the sensor control device using an identity resolution key, andwherein the resolvable address comprises: a first portion of which isbased on a randomly generated number; and a second portion of which isbased on the identity resolution key.
 8. The method of claim 7, furthercomprising: receiving, by a reader device, at least one of the firstadvertisement packets or the second advertisement packets, wherein theat least one of the first advertisement packets or the secondadvertisement packets comprises the resolvable address; retrieving, bythe reader device, the identity resolution key; and resolving, by thereader device, the identity of the sensor control device (102) using theat least one of the first advertisement packets or the secondadvertisement packets and the identity resolution key.
 9. The method ofclaim 7, further comprising: receiving, by a reader device, at least oneof the first advertisement packets or the second advertisement packets,wherein the at least one of the first advertisement packets or thesecond advertisement packets comprises a resolvable address; extractinga first portion and a second portion of the at least one of the firstadvertisement packets or the second advertisement packets; performing,by the reader device, an iterative comparison loop, the steps of theiterative comparison loop comprising: retrieving, by the reader device,an identity resolution key; generating a hash value based on theretrieved identity resolution key and the first extracted portion;comparing the generated hash value to the second extracted portion;determining, if there is a match between the generated hash value andthe second extracted portion, the identity of the sensor control device;and identifying, if there is not a match between the generated hashvalue and the second extracted portion, the next identity resolution keyto retrieve.
 10. An in vivo analyte monitoring system comprising asensor control device, the sensor control device comprising: wirelesscommunication circuitry adapted to wirelessly transmit data; one or moreprocessors; memory on which one or more instructions are stored that,when executed by the one or more processors, cause the one or moreprocessors to: generate a first address associated with the sensorcontrol device; transmit periodically, at a first advertising rate for afirst predetermined period, one or more first advertisement packetscomprising the first address; generate a second address associated withthe sensor control device, wherein the first address is different fromthe second address; and transmit periodically, at a second advertisingrate for a second predetermined period, one or more second advertisementpackets comprising the second address; and wherein the firstpredetermined period overlaps with the second predetermined period; andwherein the transmitting steps comprise wirelessly transmitting theadvertisement packets using one of a near field communication (NFC)protocol, a RFID protocol, a Bluetooth or Bluetooth Low Energy protocol,a Wi-Fi protocol, or a proprietary protocol.
 11. The system of claim 10,wherein the first advertising rate is different from the secondadvertising rate.
 12. The system of claim 10, wherein either or both ofthe first advertising rate and the second advertising rate is based atleast in part on a randomly generated number.
 13. The system of claim10, wherein the duration of the overlap between the first predeterminedperiod and the second predetermined period is based at least in part ona randomly generated number.
 14. The system of claim 10, wherein eitheror both of the first address and the second address is a randomlygenerated address.
 15. The system of claim 10, wherein at least one ofthe first address or the second address is a resolvable address, whereinthe resolvable address is adapted to be resolved to an addressassociated with the sensor control device using an identity resolutionkey, and wherein the resolvable address comprises: a first portion ofwhich is based on a randomly generated number; and a second portion ofwhich is based on the identity resolution key.
 16. The system of claim15, further comprising a reader device, the reader device comprising:wireless communication circuitry adapted to receive wirelesslytransmitted data; one or more processors; memory on which one or moreinstructions are stored that, when executed by the one or moreprocessors, cause the one or more processors to: receive at least one ofthe first advertisement packets or the second advertisement packets,wherein the at least one of the first advertisement packets or thesecond advertisement packets comprises the resolvable address; retrievethe identity resolution key; and resolve the identity of the sensorcontrol device using the at least one of the first advertisement packetsor the second advertisement packets and the identity resolution key.